Created with the express purpose of training WebArch new recruits in version control
To download git-scm https://git-scm.com/
Try this first, its really simple and you will imediately understand the basics https://try.github.io/levels/1/challenges/1
Get into some more advanced topics https://www.atlassian.com/git/tutorials
Official Docs https://git-scm.com/docs/gittutorial