Start with [Git how to](http://githowto.com/) 50 min
And if you like continue
1. [https://github.com/Gazler/githug](https://github.com/Gazler/githug) 1 hour
2. [https://www.codeschool.com/courses/git-real](https://www.codeschool.com/courses/git-real) 1 hour
3. [https://www.codeschool.com/courses/git-real-2](https://www.codeschool.com/courses/git-real-2) 1 hour
**Summary:** ~ 4 hours