diff --git a/content/courses/testing-your-first-application/how-to-test-forms-and-custom-cypress-commands.mdx b/content/courses/testing-your-first-application/how-to-test-forms-and-custom-cypress-commands.mdx
index 7e3b7409..b9f3339d 100644
--- a/content/courses/testing-your-first-application/how-to-test-forms-and-custom-cypress-commands.mdx
+++ b/content/courses/testing-your-first-application/how-to-test-forms-and-custom-cypress-commands.mdx
@@ -28,7 +28,7 @@ Cypress.Commands.add("getByData", (selector) => {
 
 :::warning
 
-Since we are using TypeScript, you may get some errors from the compiler saying that it is unable to detect the types in our custom command. You can fix this, by creating the file `cypress/support/index.ts` and adding the following:
+Since we are using TypeScript, you may get some errors from the compiler saying that it is unable to detect the types in our custom command. You can fix this, by creating the file `cypress/support/index.d.ts` and adding the following:
 
 :::