Using your Smith 21 Squad XL goggles is easy. First, adjust the dual - slide strap to fit your head comfortably. Make sure the goggles sit well on your face and align with your eyes. You can choose the appropriate ChromaPop™ lens according to the light conditions. For bright days, use the bright - light lens; for low - light situations, switch to the low - light one. When wearing a helmet, the goggles are designed to be compatible, so just put them on as usual. As for maintenance, after each use, wipe the lenses gently with the microfiber goggle bag to keep them clean. If the lenses get dirty, you can wash them with mild soap and water, then let them air - dry. Store the goggles in the provided bag when not in use to protect them from scratches. Also, be careful not to expose the goggles to extreme heat or cold, as it may affect the performance of the lenses and the frame.