The winner of the first trick in each round takes the little a into his hand. At the end of the round, if the little a is in a player's hand, it is worth 15 points. The Big A is worth 20 points to the poor soul who holds it. The A card has a value of zero. Jokers have a value of 1. 3.
Every player plays once.
And no one may pass. Whoever plays the highest card takes the trick. If you've just taken the Big A, then you have to wait until your next lead to play. These cards will be worth points at the end of the round. Fortunately, the Joker is worth 1, and the little a card is worth 0 points.