Using this Raskullz T - Rex Bonz Helmet is easy. First, make sure your toddler's head size is between 48 - 52cm, which is suitable for ages 3 - 5. Then, gently place the helmet on your child's head and adjust it until it fits snugly. When your toddler is riding a bike, scooter, or skateboard, always ensure the helmet is worn correctly. As for maintenance, you can use a soft, damp cloth to wipe the helmet clean. Avoid using harsh chemicals as they may damage the helmet. And remember, check the helmet regularly for any signs of wear and tear, and replace it if necessary.