> Take an existing game or game jam entry on GitHub, fork it and do something awesome with it.
> Take a look at the following resources to see if there's one you'd be intersted in forking....
> Once you've found a game repository, fork it...
> Make sure your code is pushed to the default branch of your forked repository...
And, on the submission form, talking about your Readme file:
> Mention the Game Off, what changes you made, who was on your team, what technologies you used, throw in a screenshot, etc.
I dunno, all that seems pretty explicit to me.