Don't over scope your project if you want to finish it for the jam. Scope is probably one of the most difficult things to limit for new game devs/jammers. You should try to complete a single level or a single vertical slice of the game then polish it up. Take whatever idea you have and write down the core mechanics for it then put anything else into a document that you can call "Stretch Goals."
You can also try to join a team with other people who have done jams before and that will let you learn a lot about it.