If the jam starts, you will know the theme and start developing a game for this theme.
There is no need to upload a project before the start of the Game Jam.
What the statement in " means is, that you should write on your itch.io project page, which you will create before the end of the Game Jam, all names of your team members to credit the whole team and not only yourself.
What I ACTUALLY wanted to say was that when you post the project once the game is done, on the project page there will be a field to add all of your team members, and you should do that so that the team members are counted as such and can rate other jam games.
