When you say you “downloaded Github” can you be more specific about what you downloaded?
And what does “codes downloaded from the side” mean? Are you trying to download code from the site?
Are you not familiar with GitHub or code repositories in general? Sounds as if you think GitHub is some framework to implement into your game like in few other game jams.
You don't need to download any specific code from the site.
It's the opposite, you will need to upload your own code.
I hope this makes it mode clear.
github is a place where you upload your code to it something like a cloud service but for code
you can make your code private or public depending on your desires
but in the rules you're supposed to make your code public to make everyone able to see it
you can search on youtube for tutorials on using github & you would only need github desktop part but if you wanna know you might also see git part