Adding instructions to generate code

Documentation/code-generation-instructions.md

@@ -0,0 +1,44 @@
+# How to generate Code
+
+To generate code, simply run the `generate.ps1` powershell script. If a powershell script does not exist under the RP directory, create one using an example [here](https://github.com/Azure/azure-sdk-for-net/blob/psSdkJson6/src/SDKs/Compute/Management.Compute/generate.ps1).
+
+If code generation fails for any reason, here a few common steps to resolve the issues.
+
+- Clean the repo
+```
+git clean -xdf
+```
+- Download and install the latest build tools (use a VS 2017 developer prompt to run msbuild)
+``` 
+msbuild build.proj
+```
+- Run the `generate.ps1` command again
+
+
+# When opening a PR
+
+## General instructions
+- Please link the REST spec API PR which helps the review process
+- Please check whether a new API version is introduced in the REST spec repo; this is important while addressing the instructions below
+- Please read the SLA information and other instructions on the PR template before opening the PR
+
+## REST API version artifacts
+If there is a new version of the REST API from which code is being generated for the PR, the following files should be modified/created in the PR
+- A `.props` file which holds information about the REST API versions eg: [here](https://github.com/Azure/azure-sdk-for-net/blob/psSdkJson6/src/SDKs/Compute/AzSdk.RP.props)
+- A `SdkInfo_*.cs` file which holds information about the REST API versions eg: [here](https://github.com/Azure/azure-sdk-for-net/blob/psSdkJson6/src/SDKs/Compute/AzSdk.RP.props)
+
+To generate the `.props` artifact, please run (use the VS 2017 developer prompt for msbuild):
+```
+msbuild build.proj /t:build /p:Scope=SDKs\<RP>
+```
+RP is the resource provider's directory under SDKs, eg.: Compute
+
+To generate the `SdkInfo*.cs` file, please run the `generate.ps1` script
+
+## Code generation artifacts
+If code is generated using `generate.ps1`, information related to the generation gets logged in a `.txt` file under `src\SDKs\_metadata` eg.: [here](https://github.com/Azure/azure-sdk-for-net/blob/psSdkJson6/src/SDKs/_metadata/compute_resource-manager.txt)
+
+Please check the branch and fork of the REST spec for which the code was generated, this must always be `Azure` and `master` respectively for a PR to be valid. Code generated using specifications not checked in the Azure master branch will not be merged.
+
+# How to sign/publish bits
+For detailed information about publishing and the overall workflow towards developing a powershell cli, click [here](https://github.com/Azure/adx-documentation-pr/blob/master/engineering/autorest-to-powershell.md)