To use this Raskullz Astro Cat Toddler Helmet, first make sure your child's head size is between 48 - 52cm. Place the helmet gently on your child's head, adjusting it so the 3D kitten nose is centered on the front. Fasten the straps under the chin snugly but not too tight. Always supervise your child when they're wearing the helmet. When it comes to maintenance, use a soft, damp cloth to wipe off dirt or debris. Don't use harsh chemicals as they might damage the glitter or graphics. Store the helmet in a cool, dry place when not in use.