When I start a game all 5 home islands are on the table as well as all 8 inner island mats. Each home islands has a "Play / Discard" component next to it. It seems I'm supposed to somehow interact with them to decide how many players and which people will play the game, but I am not sure what to do. I've tried placing each of the decks on either the Play/Discard spot, but nothing happens.