What is github? Why/when do we use it? How do we use it? And most importantly, why is it useful?
I’ve read @MakeTheBrainHappy’s post about this and also watched the video on Github. But I think I still don’t understand. Could you help?

What is version control?
As a Scratcher, you might have removed some code you thought you wouldn't need anymore, or published a change to a costume that you realized you didn't really like. Now you want to go back to the old version, but since you already edited it, it's impossible to recover! Version control lets you save a history of all the changes you've made to a directory and revert and combine them. A common version control system (VCS) is Git. Git lets you commit changes, then push them to a remote repository, like on GitHub. Many people's code gets merged and combine to work as one, and if something changed turns out to not work well, you can revert it.
GitHub gives you even more tools to work on code together. At its most basic level, it hosts Git repositories, but it can do quite a lot more.

Sorry, I wrote that really fast. I hope this helps.

GitHub is simply a platform to store code for a project and to save older versions of that code if needed. All of Scratch's open source projects are at their organization.

ZZC12345 wrote:

Git lets you commit changes, then push them to a remote repository, like on GitHub.

Additionally, it lets you create branches of commits, which let you work on changes separately from the main branch, then merge them into another branch or discard them.

You can fork and branch things on github too, and resolve issues. (and follow people.)
edit: my first post in open source projects