Using this G - Shock GA010 watch is a breeze. To access the world time and stopwatch features, just press the relevant buttons on the side of the watch. For the high - brightness LED light, press the large button on the front of the case. When it comes to battery, since it has a 10 - year battery life, you don't need to worry about changing it often. But when the time comes, take it to a professional watch repairer to replace the CR2025 battery. As for maintenance, keep it away from extreme temperatures and strong magnetic fields. After exposure to water, dry it gently with a soft cloth. It has 200 - meter water resistance, but avoid pressing buttons underwater.