Feel free to ask questions about the jam here!
Are you allowed to make music, art and stuff like that before the jam starts?
Yes you can, but you only know the theme when the Jam starts. So maybe you need to adjust for the theme...
Can you submit the game you make for this jam to other jams if it also fits the other jams theme?
Yes you can, but only if the other jam allows it. Often the rule is that you can only submit a game especially made for the jam.