Using your TAG Heuer Autavia is easy. To start the chronograph function, press the top button. Press it again to stop, and the bottom button to reset. For setting the time, pull out the crown and turn it clockwise or counter - clockwise. When you're done, push the crown back in. As for water resistance, it can withstand splashes and swimming in shallow water, but avoid high - pressure water like diving or using a jet shower. To maintain your watch, keep it clean by wiping it with a soft, dry cloth regularly. If the alligator leather band gets dirty, use a mild leather cleaner. Have the watch serviced every 3 - 5 years by a professional to ensure its long - lasting performance.