Using your LEFF Amsterdam S42 Tube Watch is easy. Just adjust the steel band to fit your wrist using the butterfly clasp. To set the time, unscrew the crown carefully and turn it to the desired time, then screw it back down. This watch is water-resistant up to 10 ATM, so it can handle splashes and short swims, but don't wear it for deep-sea diving. Keep it away from strong magnetic fields as they can affect the movement. Clean the watch regularly with a soft, dry cloth to maintain its shine. If you have any issues, our 2-year warranty has you covered, and you can return it within 30 days if it doesn't meet your expectations.