How to use GITHUB to do source

1. how to create repository
2. how to create branch
3. how to add the comment for every change
4. what is the commit
5. how to rollback
6. how to sync the sources between local and sever
   6.1 what is the pull request
   6.2 what is the push request
7. what is the relationship between branch and master
8. how to grant authority to other team members to edit your sources