Note: You will need an Alan or a Philip’s screwdriver depending on the screws in your device.
Unscrew the three screws on the two sides and bottom of the device.
Remove the cover.
Remove the battery pack on the inside of the device.
Remove the batteries.
Note the battery terminals (+, -).
Place new batteries in the battery pack (AA).
Place the battery pack back in the device. Make sure the arrows on the top are facing toward the door.
Replace the cover and screw it back in.