Using your G - Shock MRGB2000B is a breeze. For radio - controlled calibration, just make sure the watch is in an area with good signal reception. It'll automatically adjust the time for you. To connect to your smartphone via Bluetooth, go to your phone's Bluetooth settings and pair it with the watch. You can then get even more features and updates. This watch is shock - resistant, but it's still a good idea to avoid dropping it or giving it a hard knock. With 200 - metre water resistance, you can wear it while swimming or snorkeling, but don't use it for scuba diving. Keep it out of hot and humid places for long periods. The solar power feature means you don't have to worry about changing batteries often, but if you notice the watch running slow, just let it soak up some sunlight. To clean it, use a soft, dry cloth. And that's all you need to know to keep your G - Shock MRGB2000B in great shape!