Added "Set up your development environment".

CONTRIBUTING.md

@@ -16,7 +16,9 @@ You can contribute to this project by contributing to:
 * [Enums](#Enums)
 * [Projections](docs/projections.md)
 
-When contributing PRs, [validate](#Validating-changes) your changes by rebuilding the winmd and then inspecting the reported winmd diff to ensure all changes were intentional:
+If you intend to contribute code changes, learn how to [set up your development environment](#Set-up-your-development-environment).
+
+When contributing code changes, [validate](#Validating-changes) your changes by rebuilding the winmd and then inspecting the reported winmd diff to ensure all changes were intentional:
 
 * [Full builds](#Full-builds)
 * [Incremental builds](#Incremental-builds)
@@ -26,6 +28,14 @@ This project has adopted the [Microsoft Open Source Code of Conduct](https://ope
 For more information see the [Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq/) or
 contact [opencode@microsoft.com](mailto:opencode@microsoft.com) with any additional questions or comments.
 
+## Set up your development environment
+
+* Install [Visual Studio Code](https://code.visualstudio.com/Download)
+* Install [PowerShell](https://aka.ms/powershell-release?tag=stable)
+* Install [ILSpy](https://github.com/icsharpcode/ILSpy/releases/latest)
+* Clone the [repo](https://github.com/microsoft/win32metadata.git)
+* Run a [full build](#Full-builds)
+
 ## Namespaces
 
 Our tooling organizes Win32 APIs into namespaces. This provides an alternative way for developers to easily include large areas of functionality and improves consistency and discoverability across Win32 and WinRT.