Using the Bell Nomad 2 bike helmet is easy. First, adjust the Ergo Fit™ system to fit your head size. You can find the right size based on the provided measurements (S/M for 50 - 57cm and M/L for 53 - 60cm). Put on the helmet and make sure it sits comfortably on your head. Adjust the adjustable visor according to your needs, whether it's to block the sun or rain. When riding, always ensure the helmet is securely fastened. As for maintenance, use a mild soap and water to clean the helmet. Avoid using harsh chemicals as they may damage the shell or padding. After cleaning, let it air - dry in a cool place. Also, regularly check the helmet for any signs of damage, like cracks or loose parts. If you notice any issues, it's time to replace the helmet to keep you safe on the trails.