Try Git is a really fast and easy resource to get started learning Git.
I was introduced to this website through a colleague at work, and found it very helpful in getting an introduction to Git. If you’re not sure what Git is, its a version control system. So instead of making six different copies of a file as you’re working on it and changing it, you can use Git to track the different versions for you. That way you only have one file on your hard drive, but you can always get back to previous versions if you find you need to.
Bonus: GitHub has a very handy cheat sheet that you can bookmark for quick reference to commands.