A game jam is like a competition, where you have to make a game about a topic in an especific period of time, mini jam is the name of the jam. But there is no theme, so you just need to make a game with the limitations they said, the limitation was only 5 colours
maybe you should practice before you participate on a game jam, making an original game, and maybe learn other ways to make games, i recomend you to learn coding when you feel prepared, this is for experienced people, if you want to learn, watch yt videos and other things, and never think there is a limit and you can't go deeper, because there is always something to learn, with time, you'll do great things