Git, is the one of few thing you need to learn to work efficiently in a software team. That's the reason it is listed as the first item in The Joel Test: 12 Steps to Better Code
Unlike other version controls, Git is distributed. Meaning, you can continue to create locally and commit branches locally without connecting to Git hosting servers. There is no thing as central repository. Every developer can have his own copy of the entire history.
If you want to make yourself familiar with Git commands and best practises of PR, commit messages head over to My GitHub cheatsheet