Using your Met Hooray kids' helmet is easy. First, choose the right size for your child's head. Measure the diameter of their head and pick either XS/UT for 46 - 53cm or SM/UC for 52 - 55cm. Place the helmet on your child's head so that it sits level and covers the forehead and temples. Adjust the straps under the chin to ensure a snug fit. When riding, always make sure the helmet is properly fastened. For maintenance, clean the helmet with a mild soap and water solution. Avoid using harsh chemicals as they may damage the helmet. Store the helmet in a cool, dry place away from direct sunlight. Check the helmet regularly for any signs of damage, and replace it if it has been involved in an accident or shows significant wear and tear.