creates a structure for Buildpacks order page (#744)

* creates a structure for buildpacks order page
* links the buildpack group page

Signed-off-by: Hanan Younes <[email protected]>

---------

Signed-off-by: Hanan Younes <[email protected]>

content/docs/for-buildpack-authors/how-to/distribute-buildpacks/craft-order.md

@@ -3,8 +3,20 @@ title="Craft a buildpack order"
 weight=99
 +++
 
+An `order` is a list of one or more `groups` to be tested against application source code, so that the appropriate `group` for a build can be determined.
+
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-This page is a stub! The CNB project is applying to [Google Season of Docs](https://developers.google.com/season-of-docs/docs/timeline) to receive support for improving our documentation. Please check back soon.
+Whereas a `buildpack group`, or `group`, is a list of one or more buildpacks that are designed to work together. For example, a buildpack that provides `node` and a buildpack that provides `npm`.
+
+During the `detect` phase, an order definition for buildpacks and an order definition for image extensions—if present—MUST be resolved into a group of component buildpacks and a group of image extensions.
+
+## Composite Buildpacks
+
+A **composite buildpack** is a buildpack that doesn't contain any `/bin/detect` or `/bin/build` executables; instead it references other buildpacks in its `buildpack.toml` via the `[[order]]` array. Composite buildpacks MUST be [resolvable](https://github.com/buildpacks/spec/blob/main/buildpack.md#order-resolution) into a collection of component buildpacks. That is, after the [detect phase](https://buildpacks.io/docs/for-buildpack-authors/concepts/lifecycle-phases/#phase-2-detect) of the lifecycle has completed, a single group of component buildpacks from the `[[order]]` array will have opted in to the build.
+
+## Why use Composite Buildpacks
+
+Most advanced buildpacks aren’t actually a single buildpack, but instead a composite or an ordered list of component buildpacks with each buildpack performing specific jobs. This is useful for composing more complex detection strategies.
 
-If you are familiar with this content and would like to make a contribution, please feel free to open a PR :)
+>For more details on composite buildpacks, buildpack groups, and order resolution, see the [concept page](https://buildpacks.io/docs/for-buildpack-authors/concepts/buildpack-group/) for buildpack groups.