You can find git here. To make your life easier, you may want to also download a gui.
The official website is a great resource. However, if you really want to learn (and have 15 minutes of spare time), play with this. It's free. :-)
Also, great cheat-sheet.
And reasons to use version control
To use git from Matlab, first install git from the links above. Then, download this and add it to matlab's path.
You can also use git from within RStudio and from most text editors. Some shells (bash, zsh, fish, etc.) also have the option of showing you the status of a git repo in the command line.