The 5 extra turns booster is automatically applied to the next game you happen to play. You probably don’t even notice it exists! Unbelievably, there is no way to toggle it off or on. The ones I happen to get are usually wasted on level 1 of whatever event happens to be running at the time; today it was the chicken coop. I have no idea why this booster can’t be banked like in the other King games.