Using this 100% Altis mountain bike helmet is easy. First, choose the right size from XS/S, S/M, or L/XL to ensure a snug fit. Put the helmet on your head and adjust the straps so it stays firmly in place. When you're riding, the adjustable visor can be set according to your needs, and it's great for storing your 100% eyewear and goggles. As for maintenance, keep it clean by using a mild soap and water solution to wipe it down. Avoid using harsh chemicals as they might damage the shell or the liner. Also, check the helmet regularly for any signs of wear and tear, and replace it if there's any significant damage.