To use the Hot Wheels City T - Rex Chomp Down Playset, first place the included 1:64 scale Hot Wheels car in the police station. Then, hit the slam launcher to send the car through the 9 - inch loop towards the defeat zone. Try to time it right to knock out the T - Rex. When it falls, you'll see its eyes change from angry to X - es. Remember, this set is for kids 4 years old and up. As for maintenance, keep the set clean and dry. If it gets dirty, you can use a soft, dry cloth to wipe it. Avoid using harsh chemicals as they may damage the set. Also, be careful when connecting it to other sets to prevent any breakage. Enjoy building your Hot Wheels City!