Git is not Github, I tend to confuse things. Git is software, a version control system to track file changes, while GitHub is a service on the web to host projects versioned with Git. I host everything in Github; why? Cause they gave me the Pro version for free while I was studying; I'm that simple. But you could decide to pass and have just local projects or use another host; there are many.

I will not go over the commands here; it's much more fun playing with this interactive tutorial, and seeing the branches moving with the exercises made me understand faster than reading articles. If you try it, you may appreciate the levels that let you go to the parts you feel less confident about.

Then, after that, learning that Github (not Git) has a command to squash and merge PR's maybe can turn helpful, in which context? Ok, I might want to go over some commands after all...