chore: updating contributing.md (#1010)

b/323270504

CONTRIBUTING.md

@@ -1,4 +1,9 @@
-Want to contribute? Great! First, read this page (including the small print at the end).
+Please follow the guidelines below before opening an issue or a PR:
+
+1. Ensure the issue was not already reported.
+2. Open a new issue if you are unable to find an existing issue addressing your problem. Make sure to include a title and clear description, as much relevant information as possible, and a code sample or an executable test case demonstrating the expected behavior that is not occurring.
+3. Discuss the priority and potential solutions with the maintainers in the issue. The maintainers would review the issue and add a label "Accepting Contributions" once the issue is ready for accepting contributions.
+4. Open a PR only if the issue is labeled with "Accepting Contributions", ensure the PR description clearly describes the problem and solution. Note that an open PR without an issues labeled with "Accepting Contributions" will not be accepted.
 
 ### Before you contribute
 Before we can use your code, you must sign the
@@ -30,4 +35,4 @@ Before submitting a pull request, please make sure to:
 Contributions made by corporations are covered by a different agreement than
 the one above, the
 [Software Grant and Corporate Contributor License Agreement]
-(https://cla.developers.google.com/about/google-corporate).
+(https://cla.developers.google.com/about/google-corporate).