diff --git a/data/duke.txt b/data/duke.txt
new file mode 100644
index 000000000..5da82cfb6
--- /dev/null
+++ b/data/duke.txt
@@ -0,0 +1,2 @@
+T | 0 | sleep
+E | 0 | go to school | monday | tuesday
diff --git a/docs/README.md b/docs/README.md
index 47b9f984f..b5ea989aa 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -1,30 +1,113 @@
-# Duke User Guide
 
-// Update the title above to match the actual product name
+# Poirot User Guide
 
-// Product screenshot goes here
+Poirot is a powerful command-line task management application designed to help you organize your to-dos, deadlines, and events efficiently.
 
-// Product intro goes here
+## Adding a To-Do
+
+Add tasks without any specific deadline or time, allowing you to track general tasks.
+
+Example: `todo Buy groceries`
+
+This command adds a new to-do task to your list.
+
+```
+____________________________________________________________
+Got it. I've added this task:
+  [T][ ] Buy groceries
+Now you have 1 tasks in the list.
+____________________________________________________________
+```
 
 ## Adding deadlines
 
-// Describe the action and its outcome.
+Add tasks with specific due dates and times to keep track of important deadlines.
+
+Example: `deadline Submit report /by 2023-12-31 2359`
+
+This command adds a new deadline task to your list.
+
+```
+____________________________________________________________
+Got it. I've added this task:
+  [D][ ] Submit report (by: Dec 31 2023, 11:59 PM)
+Now you have 1 tasks in the list.
+____________________________________________________________
+```
+
+## Adding events
+
+Create events with start and end times to manage your schedule effectively.
+
+Example: `event Team meeting /from 2023-11-15 1400 /to 2023-11-15 1500`
+
+This command adds a new event to your task list.
+
+```
+____________________________________________________________
+Got it. I've added this task:
+  [E][ ] Team meeting (from: Nov 15 2023, 02:00 PM to: Nov 15 2023, 03:00 PM)
+Now you have 2 tasks in the list.
+____________________________________________________________
+```
+
+## Listing tasks
 
-// Give examples of usage
+View all your current tasks in one place.
 
-Example: `keyword (optional arguments)`
+Example: `list`
 
-// A description of the expected outcome goes here
+This command displays all tasks currently in your list.
 
 ```
-expected output
+____________________________________________________________
+1.[D][ ] Submit report (by: Dec 31 2023, 11:59 PM)
+2.[E][ ] Team meeting (from: Nov 15 2023, 02:00 PM to: Nov 15 2023, 03:00 PM)
+____________________________________________________________
 ```
 
-## Feature ABC
+## Marking tasks as done
 
-// Feature details
+Keep track of your progress by marking completed tasks.
 
+Example: `mark 1`
 
-## Feature XYZ
+This command marks the first task in your list as done.
+
+```
+____________________________________________________________
+Nice! I've marked this task as done:
+
+[X] Submit report
+____________________________________________________________
+```
+
+## Finding tasks
+
+Quickly locate tasks related to specific keywords.
+
+Example: `find report`
+
+This command searches for tasks containing the word "report".
+
+```
+Here are the matching tasks in your list:
+1. [D][X] Submit report (by: Dec 31 2023, 11:59 PM)
+```
+
+## Deleting tasks
+
+Remove tasks that are no longer needed.
+
+Example: `delete 2`
+
+This command deletes the second task in your list.
+
+```
+____________________________________________________________
+Noted. I've removed this task:
+  [E][ ] Team meeting (from: Nov 15 2023, 02:00 PM to: Nov 15 2023, 03:00 PM)
+Now you have 1 tasks in the list.
+____________________________________________________________
+```
 
-// Feature details
\ No newline at end of file
diff --git a/src/main/java/AddDeadlineCommand.class b/src/main/java/AddDeadlineCommand.class
new file mode 100644
index 000000000..692e86ed1
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diff --git a/src/main/java/AddDeadlineCommand.java b/src/main/java/AddDeadlineCommand.java
new file mode 100644
index 000000000..cb24f3588
--- /dev/null
+++ b/src/main/java/AddDeadlineCommand.java
@@ -0,0 +1,43 @@
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeParseException;
+
+/**
+ * Command to add a deadline task.
+ */
+public class AddDeadlineCommand extends Command {
+    private String description;
+    private String by;
+    private static final DateTimeFormatter INPUT_FORMAT = DateTimeFormatter.ofPattern("yyyy-MM-dd HHmm");
+
+    /**
+     * Constructs an AddDeadlineCommand with the specified input.
+     *
+     * @param input The user input containing the task description and deadline.
+     */
+    public AddDeadlineCommand(String input) {
+        String[] parts = input.split("/by");
+        this.description = parts[0].trim().substring(9).trim();
+        this.by = parts[1].trim();
+    }
+
+    /**
+     * Executes the command to add the deadline task to the task list.
+     *
+     * @param tasks   The task list to which the task will be added.
+     * @param ui      The user interface for displaying messages to the user.
+     * @param storage The storage for saving tasks to a file.
+     */
+    @Override
+    public void execute(TaskList tasks, Ui ui, Storage storage) {
+        try {
+            LocalDateTime.parse(by, INPUT_FORMAT); // Validate the date format
+            Task newTask = new Deadline(description, by);
+            tasks.add(newTask);
+            ui.showAddedTask(newTask, tasks.getTaskCount());
+            storage.saveTasksToFile(tasks.getTasks(), tasks.getTaskCount());
+        } catch (DateTimeParseException e) {
+            ui.showError("Invalid date format. Please use yyyy-MM-dd HHmm format.");
+        }
+    }
+}
diff --git a/src/main/java/AddEventCommand.class b/src/main/java/AddEventCommand.class
new file mode 100644
index 000000000..6de7d0b8e
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diff --git a/src/main/java/AddEventCommand.java b/src/main/java/AddEventCommand.java
new file mode 100644
index 000000000..55cc60f41
--- /dev/null
+++ b/src/main/java/AddEventCommand.java
@@ -0,0 +1,39 @@
+/**
+ * Represents a command to add a new event to the task list.
+ * This command creates a new Event task with a description, start time, and end time.
+ */
+public class AddEventCommand extends Command {
+    private String description;
+    private String from;
+    private String to;
+
+    /**
+     * Constructs a new AddEventCommand with the specified event details.
+     *
+     * @param description The description of the event.
+     * @param from        The start time/date of the event.
+     * @param to          The end time/date of the event.
+     */
+    public AddEventCommand(String description, String from, String to) {
+        this.description = description;
+        this.from = from;
+        this.to = to;
+    }
+
+    /**
+     * Executes the command to add a new event to the task list.
+     * This method creates a new Event, adds it to the task list, updates the UI,
+     * and saves the updated task list to storage.
+     *
+     * @param tasks   The TaskList to which the new event will be added.
+     * @param ui      The Ui object used to display output to the user.
+     * @param storage The Storage object used to save the updated task list.
+     */
+    @Override
+    public void execute(TaskList tasks, Ui ui, Storage storage) {
+        Task newTask = new Event(description, from, to);
+        tasks.add(newTask);
+        ui.showAddedTask(newTask, tasks.getTaskCount());
+        storage.saveTasksToFile(tasks.getTasks(), tasks.getTaskCount());
+    }
+}
diff --git a/src/main/java/AddTodoCommand.class b/src/main/java/AddTodoCommand.class
new file mode 100644
index 000000000..215b4bf56
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diff --git a/src/main/java/AddTodoCommand.java b/src/main/java/AddTodoCommand.java
new file mode 100644
index 000000000..bf922e5db
--- /dev/null
+++ b/src/main/java/AddTodoCommand.java
@@ -0,0 +1,30 @@
+/**
+ * Command to add a todo task.
+ */
+public class AddTodoCommand extends Command {
+    private String description;
+
+    /**
+     * Constructs an AddTodoCommand with the specified description.
+     *
+     * @param description The description of the todo task.
+     */
+    public AddTodoCommand(String description) {
+        this.description = description;
+    }
+
+    /**
+     * Executes the command to add the todo task to the task list.
+     *
+     * @param tasks   The task list to which the task will be added.
+     * @param ui      The user interface for displaying messages to the user.
+     * @param storage The storage for saving tasks to a file.
+     */
+    @Override
+    public void execute(TaskList tasks, Ui ui, Storage storage) {
+        Task newTask = new Todo(description);
+        tasks.add(newTask);
+        ui.showAddedTask(newTask, tasks.getTaskCount());
+        storage.saveTasksToFile(tasks.getTasks(), tasks.getTaskCount());
+    }
+}
diff --git a/src/main/java/Command.class b/src/main/java/Command.class
new file mode 100644
index 000000000..3b58bf141
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diff --git a/src/main/java/Command.java b/src/main/java/Command.java
new file mode 100644
index 000000000..7f959fbf4
--- /dev/null
+++ b/src/main/java/Command.java
@@ -0,0 +1,27 @@
+/**
+ * Represents an abstract command in the task management system.
+ * This class serves as a base for all concrete command implementations.
+ */
+public abstract class Command {
+    /**
+     * Executes the command.
+     * This method should be implemented by all concrete command classes to define
+     * their specific behavior.
+     *
+     * @param tasks   The TaskList on which the command operates.
+     * @param ui      The Ui object used to interact with the user.
+     * @param storage The Storage object used to save and load tasks.
+     * @throws PoirotException If an error occurs during command execution.
+     */
+    public abstract void execute(TaskList tasks, Ui ui, Storage storage) throws PoirotException;
+
+    /**
+     * Checks if this command should exit the program.
+     * By default, commands do not exit the program.
+     *
+     * @return true if the program should exit after this command, false otherwise.
+     */
+    public boolean isExit() {
+        return false;
+    }
+}
diff --git a/src/main/java/Deadline.class b/src/main/java/Deadline.class
new file mode 100644
index 000000000..3169ee89f
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diff --git a/src/main/java/Deadline.java b/src/main/java/Deadline.java
new file mode 100644
index 000000000..f73f6a1c7
--- /dev/null
+++ b/src/main/java/Deadline.java
@@ -0,0 +1,43 @@
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+
+/**
+ * Represents a deadline task in the task management system.
+ * A deadline task is a task that needs to be completed by a specific date and time.
+ */
+public class Deadline extends Task {
+    private LocalDateTime by;
+    private static final DateTimeFormatter INPUT_FORMAT = DateTimeFormatter.ofPattern("yyyy-MM-dd HHmm");
+    private static final DateTimeFormatter OUTPUT_FORMAT = DateTimeFormatter.ofPattern("MMM d yyyy, hh:mm a");
+
+    /**
+     * Constructs a new Deadline task with the given description and deadline.
+     *
+     * @param description The description of the deadline task.
+     * @param by          The deadline date and time in the format "yyyy-MM-dd HHmm".
+     */
+    public Deadline(String description, String by) {
+        super(description);
+        this.by = LocalDateTime.parse(by, INPUT_FORMAT);
+    }
+
+    /**
+     * Returns a string representation of the deadline task.
+     *
+     * @return A formatted string representing the deadline task, including its status, description, and deadline.
+     */
+    @Override
+    public String toString() {
+        return "[D][" + getStatusIcon() + "] " + description + " (by: " + by.format(OUTPUT_FORMAT) + ")";
+    }
+
+    /**
+     * Returns a string representation of the deadline task for file storage.
+     *
+     * @return A formatted string representing the deadline task for saving to a file.
+     */
+    @Override
+    public String toFileString() {
+        return "D | " + (isDone ? "1" : "0") + " | " + description + " | " + by.format(INPUT_FORMAT);
+    }
+}
diff --git a/src/main/java/DeleteCommand.class b/src/main/java/DeleteCommand.class
new file mode 100644
index 000000000..c040f7cf9
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diff --git a/src/main/java/DeleteCommand.java b/src/main/java/DeleteCommand.java
new file mode 100644
index 000000000..17c960324
--- /dev/null
+++ b/src/main/java/DeleteCommand.java
@@ -0,0 +1,34 @@
+/**
+ * Command to delete a task from the task list.
+ */
+public class DeleteCommand extends Command {
+    private int index;
+
+    /**
+     * Constructs a DeleteCommand with the specified index.
+     *
+     * @param index The index of the task to delete.
+     */
+    public DeleteCommand(int index) {
+        this.index = index;
+    }
+
+    /**
+     * Executes the command to delete the specified task from the task list.
+     *
+     * @param tasks   The task list from which the task will be deleted.
+     * @param ui      The user interface for displaying messages to the user.
+     * @param storage The storage for saving tasks to a file.
+     * @throws PoirotException If the index is out of bounds.
+     */
+    @Override
+    public void execute(TaskList tasks, Ui ui, Storage storage) throws PoirotException {
+        if (index < 1 || index > tasks.getTaskCount()) {
+            throw new PoirotException("Task number is out of bounds!");
+        }
+        Task taskToDelete = tasks.getTask(index - 1);
+        tasks.delete(index - 1);
+        ui.showDeletedTask(taskToDelete, tasks.getTaskCount());
+        storage.saveTasksToFile(tasks.getTasks(), tasks.getTaskCount());
+    }
+}
diff --git a/src/main/java/Duke.class b/src/main/java/Duke.class
new file mode 100644
index 000000000..4fa6a3709
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diff --git a/src/main/java/Duke.java b/src/main/java/Duke.java
deleted file mode 100644
index 5d313334c..000000000
--- a/src/main/java/Duke.java
+++ /dev/null
@@ -1,10 +0,0 @@
-public class Duke {
-    public static void main(String[] args) {
-        String logo = " ____        _        \n"
-                + "|  _ \\ _   _| | _____ \n"
-                + "| | | | | | | |/ / _ \\\n"
-                + "| |_| | |_| |   <  __/\n"
-                + "|____/ \\__,_|_|\\_\\___|\n";
-        System.out.println("Hello from\n" + logo);
-    }
-}
diff --git a/src/main/java/Event.class b/src/main/java/Event.class
new file mode 100644
index 000000000..44b00bde7
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diff --git a/src/main/java/Event.java b/src/main/java/Event.java
new file mode 100644
index 000000000..d5c4cdda8
--- /dev/null
+++ b/src/main/java/Event.java
@@ -0,0 +1,44 @@
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+
+public class Event extends Task {
+    private LocalDateTime from;
+    private LocalDateTime to;
+    private static final DateTimeFormatter inputFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HHmm");
+    private static final DateTimeFormatter outputFormatter = DateTimeFormatter.ofPattern("MMM dd yyyy, HH:mm");
+
+    /**
+     * Constructs an Event with the specified description, from, and to time.
+     *
+     * @param description The description of the event.
+     * @param from        The starting time of the event in 'yyyy-MM-dd HHmm' format.
+     * @param to          The ending time of the event in 'yyyy-MM-dd HHmm' format.
+     */
+    public Event(String description, String from, String to) {
+        super(description);
+        this.from = LocalDateTime.parse(from, inputFormatter);
+        this.to = LocalDateTime.parse(to, inputFormatter);
+    }
+
+    /**
+     * Returns a string representation of the event task.
+     *
+     * @return A formatted string of the event task.
+     */
+    @Override
+    public String toString() {
+        return "[E][" + getStatusIcon() + "] " + description + " (from: "
+                + from.format(outputFormatter) + " to: " + to.format(outputFormatter) + ")";
+    }
+
+    /**
+     * Returns a string representation for saving the event task to a file.
+     *
+     * @return A formatted string of the event task for file storage.
+     */
+    @Override
+    public String toFileString() {
+        return "E | " + (isDone ? "1" : "0") + " | " + description + " | "
+                + from.format(inputFormatter) + " | " + to.format(inputFormatter);
+    }
+}
diff --git a/src/main/java/ExitCommand.class b/src/main/java/ExitCommand.class
new file mode 100644
index 000000000..9a437394f
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diff --git a/src/main/java/ExitCommand.java b/src/main/java/ExitCommand.java
new file mode 100644
index 000000000..611ff78f4
--- /dev/null
+++ b/src/main/java/ExitCommand.java
@@ -0,0 +1,26 @@
+/**
+ * Command to exit the application.
+ */
+public class ExitCommand extends Command {
+    /**
+     * Executes the command to exit the application.
+     *
+     * @param tasks   The task list (not used).
+     * @param ui      The user interface for displaying messages to the user.
+     * @param storage The storage for saving tasks to a file (not used).
+     */
+    @Override
+    public void execute(TaskList tasks, Ui ui, Storage storage) {
+        ui.showExit();
+    }
+
+    /**
+     * Indicates whether this command is an exit command.
+     *
+     * @return true, since this command is an exit command.
+     */
+    @Override
+    public boolean isExit() {
+        return true;
+    }
+}
diff --git a/src/main/java/FindCommand.class b/src/main/java/FindCommand.class
new file mode 100644
index 000000000..764aeea33
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diff --git a/src/main/java/FindCommand.java b/src/main/java/FindCommand.java
new file mode 100644
index 000000000..65ae8ce72
--- /dev/null
+++ b/src/main/java/FindCommand.java
@@ -0,0 +1,34 @@
+import java.util.ArrayList;
+
+/**
+ * Command to find tasks matching a specified keyword.
+ */
+public class FindCommand extends Command {
+    private String keyword;
+
+    /**
+     * Constructs a FindCommand with the specified keyword.
+     *
+     * @param keyword The keyword to search for in the task descriptions.
+     */
+    public FindCommand(String keyword) {
+        this.keyword = keyword.trim();
+    }
+
+    /**
+     * Executes the command to find tasks in the task list that match the keyword.
+     *
+     * @param tasks   The task list to search for matching tasks.
+     * @param ui      The user interface for displaying messages to the user.
+     * @param storage The storage for saving tasks to a file (not used).
+     */
+    @Override
+    public void execute(TaskList tasks, Ui ui, Storage storage) {
+        ArrayList<Task> foundTasks = tasks.findTasks(keyword);
+        if (foundTasks.isEmpty()) {
+            ui.showMessage("No tasks found with the keyword: " + keyword);
+        } else {
+            ui.showFoundTasks(foundTasks);
+        }
+    }
+}
diff --git a/src/main/java/ListCommand.class b/src/main/java/ListCommand.class
new file mode 100644
index 000000000..f54b80436
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diff --git a/src/main/java/ListCommand.java b/src/main/java/ListCommand.java
new file mode 100644
index 000000000..e60852602
--- /dev/null
+++ b/src/main/java/ListCommand.java
@@ -0,0 +1,16 @@
+/**
+ * Command to list all tasks in the task list.
+ */
+public class ListCommand extends Command {
+    /**
+     * Executes the command to display the list of tasks.
+     *
+     * @param tasks   The task list to display.
+     * @param ui      The user interface for displaying messages to the user.
+     * @param storage The storage for saving tasks to a file (not used).
+     */
+    @Override
+    public void execute(TaskList tasks, Ui ui, Storage storage) {
+        ui.showTaskList(tasks.getTasks(), tasks.getTaskCount());
+    }
+}
diff --git a/src/main/java/META-INF/MANIFEST.MF b/src/main/java/META-INF/MANIFEST.MF
new file mode 100644
index 000000000..bf4a2bebf
--- /dev/null
+++ b/src/main/java/META-INF/MANIFEST.MF
@@ -0,0 +1,3 @@
+Manifest-Version: 1.0
+Main-Class: Poirot
+
diff --git a/src/main/java/MarkCommand.class b/src/main/java/MarkCommand.class
new file mode 100644
index 000000000..54dcb1e1b
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diff --git a/src/main/java/MarkCommand.java b/src/main/java/MarkCommand.java
new file mode 100644
index 000000000..0dde56510
--- /dev/null
+++ b/src/main/java/MarkCommand.java
@@ -0,0 +1,33 @@
+/**
+ * Command to mark a task as done.
+ */
+public class MarkCommand extends Command {
+    private int index;
+
+    /**
+     * Constructs a MarkCommand with the specified index.
+     *
+     * @param index The index of the task to mark as done.
+     */
+    public MarkCommand(int index) {
+        this.index = index;
+    }
+
+    /**
+     * Executes the command to mark the specified task as done.
+     *
+     * @param tasks   The task list containing the task to mark.
+     * @param ui      The user interface for displaying messages to the user.
+     * @param storage The storage for saving tasks to a file.
+     * @throws PoirotException If the index is out of bounds.
+     */
+    @Override
+    public void execute(TaskList tasks, Ui ui, Storage storage) throws PoirotException {
+        if (index < 1 || index > tasks.getTaskCount()) {
+            throw new PoirotException("Task number is out of bounds!");
+        }
+        tasks.markTask(index - 1, true);
+        ui.showMarkTask(tasks.getTask(index - 1));
+        storage.saveTasksToFile(tasks.getTasks(), tasks.getTaskCount());
+    }
+}
diff --git a/src/main/java/Parser.class b/src/main/java/Parser.class
new file mode 100644
index 000000000..e80c83dbc
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diff --git a/src/main/java/Parser.java b/src/main/java/Parser.java
new file mode 100644
index 000000000..6d08d2916
--- /dev/null
+++ b/src/main/java/Parser.java
@@ -0,0 +1,92 @@
+/**
+ * The Parser class is responsible for parsing user input and creating appropriate Command objects.
+ */
+public class Parser {
+    /**
+     * Parses the input string and returns the corresponding Command object.
+     *
+     * @param input The user input string to be parsed.
+     * @return A Command object based on the parsed input.
+     * @throws PoirotException If the input is invalid or cannot be parsed.
+     */
+    public static Command parse(String input) throws PoirotException {
+        String[] list_input = input.split(" ");
+        switch (list_input[0]) {
+            case "list":
+                return new ListCommand();
+            case "mark":
+                return new MarkCommand(Integer.parseInt(list_input[1]));
+            case "unmark":
+                return new UnmarkCommand(Integer.parseInt(list_input[1]));
+            case "todo":
+                return new AddTodoCommand(input.substring(5).trim());
+            case "deadline":
+                return parseDeadlineCommand(input);
+            case "event":
+                return parseEventCommand(input);
+            case "delete":
+                return new DeleteCommand(Integer.parseInt(list_input[1]));
+            case "find":
+                return new FindCommand(input);
+            case "bye":
+                return new ExitCommand();
+            default:
+                throw new PoirotException("Unknown command!");
+        }
+    }
+    /**
+     * Parses the deadline command input and creates an AddDeadlineCommand object.
+     *
+     * @param input The deadline command input string.
+     * @return An AddDeadlineCommand object.
+     * @throws PoirotException If the deadline format is invalid.
+     */
+    private static Command parseDeadlineCommand(String input) throws PoirotException {
+        try {
+            String[] parts = input.split("/by");
+            if (parts.length < 2) {
+                throw new PoirotException("Invalid deadline format! Use: deadline <description> /by <yyyy-mm-dd>");
+            }
+            String description = parts[0].trim();
+            String by = parts[1].trim();
+            return new AddDeadlineCommand(description + " /by " + by);
+        } catch (ArrayIndexOutOfBoundsException e) {
+            throw new PoirotException("Invalid format for deadline command.");
+        }
+    }
+    /**
+     * Parses the event command input and creates an AddEventCommand object.
+     *
+     * @param input The event command input string.
+     * @return An AddEventCommand object.
+     * @throws PoirotException If the event format is invalid.
+     */
+    private static Command parseEventCommand(String input) throws PoirotException {
+        try {
+            if (!input.contains("/from") || !input.contains("/to")) {
+                throw new PoirotException("Invalid event format! Use: event <description> /from <start> /to <end>");
+            }
+
+            String[] fromParts = input.split("/from");
+            if (fromParts.length < 2) {
+                throw new PoirotException("Invalid event format! Use: event <description> /from <start> /to <end>");
+            }
+
+            String description = fromParts[0].trim().substring(6).trim();
+
+            String[] toParts = fromParts[1].split("/to");
+            if (toParts.length < 2) {
+                throw new PoirotException("Invalid event format! Use: event <description> /from <start> /to <end>");
+            }
+
+            String from = toParts[0].trim();
+            String to = toParts[1].trim();
+
+            return new AddEventCommand(description, from, to);
+        } catch (StringIndexOutOfBoundsException e) {
+            throw new PoirotException("Error extracting event description. Please check your input format.");
+        }
+    }
+
+
+}
diff --git a/src/main/java/Poirot.class b/src/main/java/Poirot.class
new file mode 100644
index 000000000..da34a1d60
Binary files /dev/null and b/src/main/java/Poirot.class differ
diff --git a/src/main/java/Poirot.java b/src/main/java/Poirot.java
new file mode 100644
index 000000000..02fd881e9
--- /dev/null
+++ b/src/main/java/Poirot.java
@@ -0,0 +1,58 @@
+/**
+ * The main class for the Poirot task management application.
+ * This class initializes the application, loads saved tasks, and runs the main command loop.
+ */
+public class Poirot {
+
+    private Storage storage;
+    private TaskList tasks;
+    private Ui ui;
+
+    /**
+     * Constructs a new Poirot application instance.
+     * Initializes the UI, storage, and task list, and loads any previously saved tasks.
+     *
+     * @param filePath The file path for storing and loading tasks.
+     */
+    public Poirot(String filePath) {
+        ui = new Ui();
+        storage = new Storage(filePath);
+        tasks = new TaskList();
+
+        Task[] loadedTasks = storage.loadTasksFromFile();
+        for (Task task : loadedTasks) {
+            if (task != null) {
+                tasks.add(task);
+            }
+        }
+    }
+
+    /**
+     * Runs the main command loop of the application.
+     * Continuously reads user input, executes commands, and displays results until an exit command is given.
+     */
+    public void run() {
+        ui.showWelcome();
+        boolean isExit = false;
+        while (!isExit) {
+            try {
+                String fullCommand = ui.readCommand();
+                Command command = Parser.parse(fullCommand);
+                command.execute(tasks, ui, storage);
+                isExit = command.isExit();
+            } catch (PoirotException e) {
+                ui.showError(e.getMessage());
+            }
+        }
+    }
+
+    /**
+     * The main entry point for the Poirot application.
+     * Creates a new Poirot instance and starts running it.
+     *
+     * @param args Command line arguments (not used).
+     */
+    public static void main(String[] args) {
+        new Poirot("./data/duke.txt").run();
+    }
+}
diff --git a/src/main/java/PoirotException.class b/src/main/java/PoirotException.class
new file mode 100644
index 000000000..92234d430
Binary files /dev/null and b/src/main/java/PoirotException.class differ
diff --git a/src/main/java/PoirotException.java b/src/main/java/PoirotException.java
new file mode 100644
index 000000000..6817ab4a6
--- /dev/null
+++ b/src/main/java/PoirotException.java
@@ -0,0 +1,14 @@
+/**
+ * Represents a custom exception for the Poirot task management application.
+ * This exception is used to handle application-specific errors and provide meaningful error messages.
+ */
+public class PoirotException extends Exception {
+    /**
+     * Constructs a new PoirotException with the specified error message.
+     *
+     * @param message The detailed error message explaining the reason for the exception.
+     */
+    public PoirotException(String message) {
+        super(message);
+    }
+}
diff --git a/src/main/java/Storage.class b/src/main/java/Storage.class
new file mode 100644
index 000000000..15438ee4e
Binary files /dev/null and b/src/main/java/Storage.class differ
diff --git a/src/main/java/Storage.java b/src/main/java/Storage.java
new file mode 100644
index 000000000..f4a177e7f
--- /dev/null
+++ b/src/main/java/Storage.java
@@ -0,0 +1,90 @@
+import java.io.*;
+import java.util.Scanner;
+
+/**
+ * Handles loading and saving tasks to a file.
+ */
+public class Storage {
+    private String filePath;
+
+    /**
+     * Constructs a Storage object with the specified file path.
+     *
+     * @param filePath The path of the file to load/save tasks.
+     */
+    public Storage(String filePath) {
+        this.filePath = filePath;
+    }
+
+    /**
+     * Loads tasks from the file and returns them as an array.
+     *
+     * @return An array of loaded tasks.
+     */
+    public Task[] loadTasksFromFile() {
+        Task[] tasks = new Task[100];
+        int lastIndex = 0;
+
+        try {
+            File file = new File(filePath);
+            if (!file.exists()) {
+                return tasks;
+            }
+
+            Scanner scanner = new Scanner(file);
+            while (scanner.hasNextLine()) {
+                String line = scanner.nextLine();
+                String[] parts = line.split(" \\| ");
+                String taskType = parts[0];
+                boolean isDone = parts[1].equals("1");
+                String description = parts[2];
+
+                switch (taskType) {
+                    case "T":
+                        tasks[lastIndex] = new Todo(description);
+                        break;
+                    case "D":
+                        String by = parts[3];
+                        tasks[lastIndex] = new Deadline(description, by);
+                        break;
+                    case "E":
+                        String from = parts[3];
+                        String to = parts[4];
+                        tasks[lastIndex] = new Event(description, from, to);
+                        break;
+                }
+
+                tasks[lastIndex].setDone(isDone);
+                lastIndex++;
+            }
+            scanner.close();
+        } catch (IOException e) {
+            System.out.println("Error loading tasks from file: " + e.getMessage());
+        }
+
+        return tasks;
+    }
+
+    /**
+     * Saves the specified tasks to the file.
+     *
+     * @param tasks     The tasks to save.
+     * @param lastIndex The number of tasks to save.
+     */
+    public void saveTasksToFile(Task[] tasks, int lastIndex) {
+        try {
+            File dir = new File("./data");
+            if (!dir.exists()) {
+                dir.mkdirs();
+            }
+
+            FileWriter writer = new FileWriter(filePath);
+            for (int i = 0; i < lastIndex; i++) {
+                writer.write(tasks[i].toFileString() + "\n");
+            }
+            writer.close();
+        } catch (IOException e) {
+            System.out.println("Error saving tasks to file: " + e.getMessage());
+        }
+    }
+}
diff --git a/src/main/java/Task.class b/src/main/java/Task.class
new file mode 100644
index 000000000..a60f77cd6
Binary files /dev/null and b/src/main/java/Task.class differ
diff --git a/src/main/java/Task.java b/src/main/java/Task.java
new file mode 100644
index 000000000..8f9059125
--- /dev/null
+++ b/src/main/java/Task.java
@@ -0,0 +1,48 @@
+/**
+ * Represents a task with a description and completion status.
+ */
+abstract class Task {
+    protected String description;
+    protected boolean isDone;
+
+    /**
+     * Constructs a Task with the specified description.
+     *
+     * @param description The description of the task.
+     */
+    public Task(String description) {
+        this.description = description;
+        this.isDone = false;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    /**
+     * Returns the status icon of the task.
+     *
+     * @return A string representing the task status icon.
+     */
+    public String getStatusIcon() {
+        return (isDone ? "X" : " ");
+    }
+
+    /**
+     * Marks the task as done or not done.
+     *
+     * @param isDone true to mark the task as done, false otherwise.
+     */
+    public void setDone(boolean isDone) {
+        this.isDone = isDone;
+    }
+
+    public abstract String toString();
+
+    /**
+     * Returns a string representation for saving the task to a file.
+     *
+     * @return A formatted string of the task for file storage.
+     */
+    public abstract String toFileString();
+}
diff --git a/src/main/java/TaskList.class b/src/main/java/TaskList.class
new file mode 100644
index 000000000..2776cf037
Binary files /dev/null and b/src/main/java/TaskList.class differ
diff --git a/src/main/java/TaskList.java b/src/main/java/TaskList.java
new file mode 100644
index 000000000..aa9abad5b
--- /dev/null
+++ b/src/main/java/TaskList.java
@@ -0,0 +1,81 @@
+import java.util.ArrayList;
+
+/**
+ * Represents a list of tasks.
+ */
+
+public class TaskList {
+    private Task[] tasks = new Task[100];
+    private int lastIndex = 0;
+
+    /**
+     * Adds a task to the task list.
+     *
+     * @param task The task to add.
+     */
+    public void add(Task task) {
+        tasks[lastIndex] = task;
+        lastIndex++;
+    }
+
+    public ArrayList<Task> findTasks(String keyword) {
+        ArrayList<Task> foundTasks = new ArrayList<>();
+        for (int i = 0; i < lastIndex; i++) {
+            if (tasks[i].getDescription().toLowerCase().contains(keyword.toLowerCase())) {
+                foundTasks.add(tasks[i]);
+            }
+        }
+        return foundTasks;
+    }
+
+    /**
+     * Deletes a task from the task list at the specified index.
+     *
+     * @param index The index of the task to delete.
+     */
+    public void delete(int index) {
+        for (int i = index; i < lastIndex - 1; i++) {
+            tasks[i] = tasks[i + 1];
+        }
+        tasks[lastIndex - 1] = null;
+        lastIndex--;
+    }
+
+    /**
+     * Returns the list of tasks.
+     *
+     * @return The list of tasks.
+     */
+    public Task[] getTasks() {
+        return tasks;
+    }
+
+    /**
+     * Returns the number of tasks in the task list.
+     *
+     * @return The count of tasks.
+     */
+    public int getTaskCount() {
+        return lastIndex;
+    }
+
+    /**
+     * Returns the task at the specified index.
+     *
+     * @param index The index of the task to retrieve.
+     * @return The task at the specified index.
+     */
+    public Task getTask(int index) {
+        return tasks[index];
+    }
+
+    /**
+     * Marks the specified task as done.
+     *
+     * @param index  The index of the task to mark.
+     * @param isDone true to mark as done, false otherwise.
+     */
+    public void markTask(int index, boolean isDone) {
+        tasks[index].setDone(isDone);
+    }
+}
diff --git a/src/main/java/Todo.class b/src/main/java/Todo.class
new file mode 100644
index 000000000..4f529c709
Binary files /dev/null and b/src/main/java/Todo.class differ
diff --git a/src/main/java/Todo.java b/src/main/java/Todo.java
new file mode 100644
index 000000000..a260ded37
--- /dev/null
+++ b/src/main/java/Todo.java
@@ -0,0 +1,33 @@
+/**
+ * Represents a simple todo task without any specific date or time.
+ */
+public class Todo extends Task {
+    /**
+     * Constructs a Todo with the specified description.
+     *
+     * @param description The description of the todo task.
+     */
+    public Todo(String description) {
+        super(description);
+    }
+
+    /**
+     * Returns the string representation of the todo task.
+     *
+     * @return The formatted string of the todo task.
+     */
+    @Override
+    public String toString() {
+        return "[T][" + getStatusIcon() + "] " + description;
+    }
+
+    /**
+     * Returns a string representation for saving the todo task to a file.
+     *
+     * @return A formatted string of the todo task for file storage.
+     */
+    @Override
+    public String toFileString() {
+        return "T | " + (isDone ? "1" : "0") + " | " + description;
+    }
+}
diff --git a/src/main/java/Ui.class b/src/main/java/Ui.class
new file mode 100644
index 000000000..e8bfcbfbd
Binary files /dev/null and b/src/main/java/Ui.class differ
diff --git a/src/main/java/Ui.java b/src/main/java/Ui.java
new file mode 100644
index 000000000..712af4ae1
--- /dev/null
+++ b/src/main/java/Ui.java
@@ -0,0 +1,132 @@
+import java.util.Scanner;
+import java.util.ArrayList;
+
+/**
+ * Handles the user interface interactions for the task management application.
+ */
+public class Ui {
+    private static final String LINE = "____________________________________________________________\n";
+
+    public void showLine() {
+        System.out.println(LINE);
+    }
+
+    public void showWelcome() {
+        showLine();
+        System.out.println("Hello! I'm POIROT\nWhat can I do for you?");
+        showLine();
+    }
+
+    /**
+     * Displays a goodbye message when exiting the application.
+     */
+    public void showExit() {
+        showLine();
+        System.out.println("Bye. Hope to see you again soon!");
+        showLine();
+    }
+
+    public String readCommand() {
+        Scanner scanner = new Scanner(System.in);
+        return scanner.nextLine();
+    }
+
+    /**
+     * Displays an error message to the user.
+     *
+     * @param message The error message to display.
+     */
+    public void showError(String message) {
+        showLine();
+        System.out.println(message);
+        showLine();
+    }
+
+    /**
+     * Displays a message indicating that a task has been added.
+     *
+     * @param task      The task that was added.
+     * @param taskCount The current count of tasks in the list.
+     */
+    public void showAddedTask(Task task, int taskCount) {
+        showLine();
+        System.out.println("Got it. I've added this task:");
+        System.out.println("  " + task);
+        System.out.println("Now you have " + taskCount + " tasks in the list.");
+        showLine();
+    }
+
+    /**
+     * Displays a message indicating that a task has been deleted.
+     *
+     * @param task      The task that was deleted.
+     * @param taskCount The current count of tasks in the list.
+     */
+    public void showDeletedTask(Task task, int taskCount) {
+        showLine();
+        System.out.println("Noted. I've removed this task:");
+        System.out.println("  " + task);
+        System.out.println("Now you have " + taskCount + " tasks in the list.");
+        showLine();
+    }
+
+    /**
+     * Displays the list of tasks to the user.
+     *
+     * @param tasks     The list of tasks to display.
+     * @param lastIndex The count of tasks in the list.
+     */
+    public void showTaskList(Task[] tasks, int lastIndex) {
+        showLine();
+        if (lastIndex == 0) {
+            System.out.println("No actions available");
+        } else {
+            for (int i = 0; i < lastIndex; i++) {
+                System.out.println((i + 1) + "." + tasks[i]);
+            }
+        }
+        showLine();
+    }
+
+    /**
+     * Displays a message indicating that a task has been marked as done.
+     *
+     * @param task The task that was marked as done.
+     */
+    public void showMarkTask(Task task) {
+        showLine();
+        System.out.println("Nice! I've marked this task as done:\n");
+        System.out.print("[" + task.getStatusIcon() + "] ");
+        System.out.println(task.getDescription());
+        showLine();
+    }
+
+    /**
+     * Displays a message indicating that a task has been unmarked as done.
+     *
+     * @param task The task that was unmarked as done.
+     */
+    public void showUnmarkTask(Task task) {
+        showLine();
+        System.out.println("OK, I've marked this task as not done yet:\n");
+        System.out.print("[" + task.getStatusIcon() + "] ");
+        System.out.println(task.getDescription());
+        showLine();
+    }
+
+    /**
+     * Displays the tasks found that match the keyword.
+     *
+     * @param tasks The list of found tasks to display.
+     */
+    public void showFoundTasks(ArrayList<Task> tasks) {
+        System.out.println("Here are the matching tasks in your list:");
+        for (int i = 0; i < tasks.size(); i++) {
+            System.out.println((i + 1) + ". " + tasks.get(i).toString());
+        }
+    }
+
+    public void showMessage(String message) {
+        System.out.println(message);
+    }
+}
diff --git a/src/main/java/UnmarkCommand.class b/src/main/java/UnmarkCommand.class
new file mode 100644
index 000000000..5a5a0dfb0
Binary files /dev/null and b/src/main/java/UnmarkCommand.class differ
diff --git a/src/main/java/UnmarkCommand.java b/src/main/java/UnmarkCommand.java
new file mode 100644
index 000000000..4f1383111
--- /dev/null
+++ b/src/main/java/UnmarkCommand.java
@@ -0,0 +1,37 @@
+/**
+ * Represents a command to unmark a task as not completed in the Poirot task management system.
+ * This command changes the status of a task from completed to not completed.
+ */
+public class UnmarkCommand extends Command {
+    private int index;
+
+    /**
+     * Constructs a new UnmarkCommand with the specified task index.
+     *
+     * @param index The index of the task to be unmarked (1-based indexing).
+     */
+    public UnmarkCommand(int index) {
+        this.index = index;
+    }
+
+    /**
+     * Executes the unmark command.
+     * This method unmarks the specified task as not completed, updates the UI,
+     * and saves the changes to storage.
+     *
+     * @param tasks   The TaskList containing all tasks.
+     * @param ui      The UI object used to display messages to the user.
+     * @param storage The Storage object used to save tasks.
+     * @throws PoirotException If the task index is out of bounds.
+     */
+
+    @Override
+    public void execute(TaskList tasks, Ui ui, Storage storage) throws PoirotException {
+        if (index < 1 || index > tasks.getTaskCount()) {
+            throw new PoirotException("Task number is out of bounds!");
+        }
+        tasks.markTask(index - 1, false);
+        ui.showUnmarkTask(tasks.getTask(index - 1));
+        storage.saveTasksToFile(tasks.getTasks(), tasks.getTaskCount());
+    }
+}
diff --git a/src/main/java/data/duke.txt b/src/main/java/data/duke.txt
new file mode 100644
index 000000000..02a909e61
--- /dev/null
+++ b/src/main/java/data/duke.txt
@@ -0,0 +1,11 @@
+T | 0 | sleep
+T | 0 | work
+T | 0 | go to work
+D | 0 | t | 2025-04-01 1800
+E | 0 | party | 2025-04-01 1800 | 2025-04-01 2100
+D | 0 | work | 2025-04-01 1800
+T | 0 | mini project
+D | 0 | uation | 2024-10-31 2359
+T | 0 | go to work
+D | 0 | peer evaluation | 2024-10-31 2359
+E | 0 | new party | 2024-11-21 1700 | 2024-11-23 1800
diff --git a/text-ui-test/EXPECTED.TXT b/text-ui-test/EXPECTED.TXT
index 657e74f6e..b4f2ce97e 100644
--- a/text-ui-test/EXPECTED.TXT
+++ b/text-ui-test/EXPECTED.TXT
@@ -1,7 +1,42 @@
-Hello from
- ____        _        
-|  _ \ _   _| | _____ 
-| | | | | | | |/ / _ \
-| |_| | |_| |   <  __/
-|____/ \__,_|_|\_\___|
+____________________________________________________________
 
+Hello! I'm POIROT
+
+What can I do for you?
+____________________________________________________________
+
+todo borrow book
+____________________________________________________________
+
+Got it. I've added this task:
+  [T][ ] borrow book
+Now you have 1 tasks in the list.
+____________________________________________________________
+
+list
+____________________________________________________________
+
+1.[T][ ] borrow book
+____________________________________________________________
+
+deadline return book /by Sunday
+____________________________________________________________
+
+Got it. I've added this task:
+  [D][ ] return book (by: Sunday)
+Now you have 2 tasks in the list.
+____________________________________________________________
+
+event project meeting /from Mon 2pm /to 4pm
+____________________________________________________________
+
+Got it. I've added this task:
+  [E][ ] project meeting (from: Mon 2pm to: 4pm)
+Now you have 3 tasks in the list.
+____________________________________________________________
+
+bye
+____________________________________________________________
+
+Bye. Hope to see you again soon!
+____________________________________________________________
\ No newline at end of file
diff --git a/text-ui-test/input.txt b/text-ui-test/input.txt
index e69de29bb..30b2c284e 100644
--- a/text-ui-test/input.txt
+++ b/text-ui-test/input.txt
@@ -0,0 +1,5 @@
+todo borrow book
+list
+deadline return book /by Sunday
+event project meeting /from Mon 2pm /to 4pm
+bye
\ No newline at end of file
diff --git a/text-ui-test/runtest.bat b/text-ui-test/runtest.bat
index 087374464..57b286e0b 100644
--- a/text-ui-test/runtest.bat
+++ b/text-ui-test/runtest.bat
@@ -7,7 +7,7 @@ REM delete output from previous run
 if exist ACTUAL.TXT del ACTUAL.TXT
 
 REM compile the code into the bin folder
-javac  -cp ..\src\main\java -Xlint:none -d ..\bin ..\src\main\java\*.java
+javac  -cp ..\src\main\java -Xlint:none -d ..\bin ..\src\main\java\Poirot.java
 IF ERRORLEVEL 1 (
     echo ********** BUILD FAILURE **********
     exit /b 1
@@ -15,7 +15,7 @@ IF ERRORLEVEL 1 (
 REM no error here, errorlevel == 0
 
 REM run the program, feed commands from input.txt file and redirect the output to the ACTUAL.TXT
-java -classpath ..\bin Duke < input.txt > ACTUAL.TXT
+java -classpath ..\bin Poirot < input.txt > ACTUAL.TXT
 
 REM compare the output to the expected output
-FC ACTUAL.TXT EXPECTED.TXT
+FC ACTUAL.TXT EXPECTED.TXT
\ No newline at end of file