When you play your next-to-last card, you must yell UNO (meaning one ) to indicate that you have only one card left. If you don't yell UNO and you are caught before the next player begins their turn, you must draw two cards. Once a player has no cards left, the round is over.
A player may play a Spin card as they would a regular number card, however, whenever a Spin card is played, the next player must spin the wheel. Spinning the wheel takes the place of that player's turn. (See THE UNO SPIN!"M WHEEL).