chore: Update README.md (#328)

* chore: Update README.md

chore: update readme for contributing guideline

* chore: Update CONTRIBUTING.md

chore: Update CONTRIBUTING.md

* Update CONTRIBUTING.md

Author: hangfei

CONTRIBUTING.md

@@ -25,9 +25,22 @@ This project follows
 
 ## Contribution process
 
+### Requirement for PRs
+
+- All PRs, other than small documentation or typo fixes, should have a Issue assoicated. If not, please create one. 
+- Small, focused PRs. Keep changes minimal—one concern per PR.
+- For bug fixes or features, please provide logs or screenshot after the fix is applied to help reviewers better understand the fix.
+- Please add corresponding testing for your code change if it's not covered by existing tests.
+
+### Large or Complex Changes
+For substantial features or architectural revisions:
+
+- Open an Issue First: Outline your proposal, including design considerations and impact.
+- Gather Feedback: Discuss with maintainers and the community to ensure alignment and avoid duplicate work
+
 ### Code reviews
 
 All submissions, including submissions by project members, require review. We
 use GitHub pull requests for this purpose. Consult
 [GitHub Help](https://help.github.com/articles/about-pull-requests/) for more
-information on using pull requests.
+information on using pull requests.

README.md

@@ -121,7 +121,9 @@ for how they can work together.
 
 ## 🤝 Contributing
 
-We welcome contributions from the community! Whether it's bug reports, feature requests, documentation improvements, or code contributions, please see our [**Contributing Guidelines**](./CONTRIBUTING.md) to get started.
+We welcome contributions from the community! Whether it's bug reports, feature requests, documentation improvements, or code contributions, please see our 
+- [General contribution guideline and flow](https://google.github.io/adk-docs/contributing-guide/#questions).
+- Then if you want to contribute code, please read [Code Contributing Guidelines](./CONTRIBUTING.md) to get started.
 
 ## 📄 License