You can also maintain parallel branches of your project. Each branch is a copy of your project.

Imagine that you have a production version of your project that lives on a website visited by millions of people each day. This production version will be your master branch. Now you want to add a new feature; for example, a button that changes the planets’ color from pink to purple. You don’t want to develop this feature in the production version. This can be dangerous as things might break and your millions of visitors might turn away in disgust. So, you create a copy of your project—a branch you might call the purple branch. You can now merrily develop locally, commit different versions of it, and make and fix mistakes. You can push your changes up to GitHub to collaborate with your friends until it works, is tested, and makes you happy. Then, you copy all changes from the purple branch to the master branch, or better expressed in Git-terminology: you merge the purple branch into the master branch.

As said, this can only be a quick tour past the bare bones of Git and GitHub. There’s surely more, but being comfortable with these key concepts and terms, you can now confidently set up yourself and your project on GitHub.