Using the Makita HR166DSMJ cordless rotary hammer drill is a breeze. First, make sure the battery is fully charged and inserted correctly into the drill. If you're going to drill, choose the appropriate SDS - PLUS bit for the material you're working on, like wood, concrete, or steel. Then, adjust the speed according to the task. For general drilling, a lower speed might be enough, but for tougher jobs, you can increase it. When using the impact function, hold the drill firmly with both hands to manage the vibrations. Always wear safety goggles and ear protection as the drill can be quite noisy. After use, remove the battery and store it in a cool, dry place. Clean the drill regularly with a dry cloth to keep it in good condition. If you notice any issues or strange noises, stop using the drill immediately and consult the manual or contact Makita's customer service.