Press C to mark someone as not the person, U to undo the marking someone, i to inspect someone (look at them closer), and press S to stop looking at them close. Click on the person to lock in your vote, and make sure that your vote is what you want because there's no undoing your click. Enjoy!
I made everything except for Mario and the image of earth on the astronaut. By the way, you need a friend with a separate device to play the game, but enjoy anyways.