To use the DEWALT DCH416B 60V MAX* rotary hammer, first make sure you've got the right drill bit for your job. Insert it into the SDS PLUS chuck firmly. Then, plug in the power source if needed. When you start the tool, apply gentle pressure and let the hammer do the work. Don't force it too hard. As for maintenance, after each use, wipe off any dust or debris from the tool. Check the drill bit for wear and tear and replace it if necessary. Keep the tool in a dry place. Remember to turn it off when not in use and always follow safety instructions in the user manual.