Using this Shimano 105 Di2 shift and brake lever is a breeze. To shift gears, just press the buttons according to your needs. You can customize these button functions through the E - TUBE app to suit your riding style. For braking, simply squeeze the lever gently, and the hydraulic disc brakes will kick in. When it comes to reach adjustment, use the provided mechanism to set the lever at a comfortable distance from your hand. As for the batteries, they are easy to replace. When the power runs low, open the battery compartment and swap out the two CR1632 batteries. In terms of maintenance, keep the lever clean by wiping it with a soft cloth regularly. Avoid exposing it to extreme temperatures and moisture. If you notice any issues with shifting or braking, check the connections and make sure the hydraulic fluid level is adequate. Always follow the instructions in the E - TUBE app for the best performance.