Using the DeWalt DCN45RNB cordless roofing nailer is easy. First, make sure the 20V Max battery is fully charged and properly inserted. Then, adjust the tool - free nail tray to fit the type of roofing nails you'll be using. To start nailing, place the nailer on the surface and use the bump mode for quick and efficient nailing. For safety, always wear appropriate protective gear like safety glasses and gloves. Keep your hands away from the nailer's firing area. When it comes to maintenance, after each use, clean the nailer to remove any debris. Check the brushless motor regularly for any signs of damage. Store the nailer in a dry place to prevent rust and other issues.