To submit your game, you have to join the jam, and then the 'Join Jam' button will be replaced by 'Submit Your Project'. You have to click that. Then, you have to click on 'Upload Game'. Set up the page. Then click 'Upload'. But it is not done yet. This happened with me this jam, I uploaded my game but it did not get submitted to the jam. You have to click the 'Submit Project' button again and then choose the first option.