How to contribute.

Author: Benoit Hudson

CONTRIBUTING.md

@@ -1,9 +1,16 @@
 # Contributing
 
 ## If you are interested in contributing, here are some ground rules:
-* ... Define guidelines & rules for what contributors need to know to successfully make Pull requests against your repo ...
+* Discuss the issue you want to solve with others. Make sure it fits with others' needs.
+* Include a link to a discussion of the issue you're solving.
+* Help the reviewers understand your work and minimize merge conflicts:
+ * Fix only one thing per pull request. Make a second pull request if you have two fixes.
+ * Try to minimize stylistic changes in your pull request. Don't change indentation and whitespace unless it's important.
+ * Try to make sure new files end in a newline, that there's no extra whitespace, that you use spaces (not tabs), and that you match the coding style of similar files.
+* Make sure to include tests. If you're fixing a bug, include a regression test -- a test that failed before your contribution.
+* Make sure all tests pass.
 
 ## All contributions are subject to the [Unity Contribution Agreement(UCA)](https://unity3d.com/legal/licenses/Unity_Contribution_Agreement)
 By making a pull request, you are confirming agreement to the terms and conditions of the UCA, including that your Contributions are your original creation and that you have complete right and authority to make your Contributions.
 
-## Once you have a change ready following these ground rules. Simply make a pull request
+## Once you have a change ready following these ground rules. Simply [make a pull request](https://help.github.com/en/articles/creating-a-pull-request-from-a-fork)