Passage: When castling, the king must be the first piece touched. If the player touches the rook at the same time as touching the king, the player must castle with that rook if it is legal to do so. If the player completes a two-square king move without touching a rook, the player must move the correct rook accordingly if castling in that direction is legal. If a player starts to castle illegally, another legal king move must be made if possible, including castling with the other rook (Schiller 2003:20).

Question: What must the king do with a new castle?
king must be the first piece touched