Using this key lock switch is easy. First, drill a 12mm diameter hole in your mounting plate. Then insert the switch. To turn it on, insert the 'bike lock' style key and rotate it clockwise one full turn. This will connect the electrical contacts. To turn it off, rotate the key counter - clockwise. Remember, since it's a momentary style, you can't remove the key when it's on. You have to turn it off first. As for maintenance, keep the key and the switch clean. Avoid using it in extremely dirty or wet environments. Also, don't use this switch in high - security situations as all the keys in an order are the same and it's not hard to pick.