If you weren't using GitHub throughout the event to push/pull/make commits to your project that's okay! You can just upload your code/files to GitHub :)
Go to GitHub and sign in (sign up for an account if you don't already have one)
Once you log in you should see a screen like this, go ahead and click that 'New Repository' button:
You'll be taken to this screen, go ahead and give your repository a name and make sure that it's set to public (so judges can see it)
Upload your files
More about file upload here: https://docs.github.com/en/github/managing-files-in-a-repository/adding-a-file-to-a-repository
A link to your GitHub repository will be required for project submissions on Devpost. If you are a first-time coder or have little to no experience using git or GitHub, we highly recommend attending our Github Workshop on Satruday 10:30 AM CST :)
Once you learn the basics of git, this cheat sheet will be helpful.
If you choose to use GitHub rather than git, this guide will be helpful.