There are many good online guides to learn more about git and GitHub and as with any open source software there is a huge community that can be a great resource:
The British Ecological Society guide to Reproducible Code
The GitHub guides
The Mozilla Science Lab GitHub for Collaboration on Open Projects guide
Jenny Bryan’s Happy Git and GitHub. We borrowed the idea (but with different content) of RStudio first, RStudio second in the ‘Setting up a version controlled Project in RStudio’ section.
Melanie Frazier’s GitHub: A beginner’s guide to going back in time (aka fixing mistakes). We followed this structure (with modifications and different content) in the ‘Reverting changes’ section.
These are only a couple of examples, all you need to do is Google “version control with git and GitHub” to see how huge the community around these open source projects is and how many free resources are available for you to become a version control expert.