Git is a popular form of source control, a way to keep a history of changes you've made to code. You can go back through changes, see what they were, restore older versions, and keep a commented log of why changes were made. Git also lets you store code in more than one location in case your hard drive fails. Git stores code and its history in repositories, or repos. In Git, you can make branches, copies of the whole set of code, to try ideas in parallel with your code and later merge those back to the main branch. I will get you started, but this section can only scratch the surface of what Git is capable of.
To install Git, please follow the instructions at https://git-scm.com/book/en/v2/Getting-Started-Installing-Git for your computer. Windows and Mac users may be able to use the GitHub app for easier setup. Git requires...