GitHub is kind of like google docs/google drive, but for code!
Here’s a guide from GitHub: https://docs.github.com/get-started and here’s an Intro to GitHub workshop:
https://www.youtube.com/watch?v=77814l_6P3E
You don’t have to use GitHub for collaborating on your code (pushing/pulling/etc.) but you will have to upload your code to GitHub for project submissions. Come to the DevPost + Pitching Your Project Workshop for more info & help!