update CONTRIBUTING.md with new information about pull requests

CONTRIBUTING.md

@@ -30,11 +30,15 @@ Contributions via pull requests are much appreciated. Before sending us a pull r
 To send us a pull request, please:
 
 1. Fork the repository.
-2. Modify the source; please focus on the specific change you are contributing. If you also reformat all the code, it will be hard for us to focus on your change.
-3. Ensure local tests pass.
-4. Commit to your fork using clear commit messages.
-5. Send us a pull request, answering any default questions in the pull request interface.
-6. Pay attention to any automated CI failures reported in the pull request, and stay involved in the conversation.
+2. Create a branch for your change.
+3. Modify the source; please focus on the specific change you are contributing. If you also reformat all the code, it will be hard for us to focus on your change.
+4. Ensure local tests pass.
+5. Commit to your fork using clear commit messages.
+6. Push that branch to the upstream `aws/sagemaker-code-editor` repository.
+7. Send us a pull request (from your branch in  `aws/sagemaker-code-editor`), answering any default questions in the pull request interface.
+
+    > ***Important***: Our tests will **always fail** if the pull request does not come from a branch in the  `aws/sagemaker-code-editor` repository. 
+8. Pay attention to any automated CI failures reported in the pull request, and stay involved in the conversation.
 
 GitHub provides additional document on [forking a repository](https://help.github.com/articles/fork-a-repo/) and
 [creating a pull request](https://help.github.com/articles/creating-a-pull-request/).