Open the product ,use small slot type screwdriver or flats tools to tilt product?s surface gap, make the diffuser separate from the bottom case and take out the middle plate. Use set screw to fasten the bottom case on the wall. Put AC wire through the bottom case hole, connect the main circuit board on L,N connect terminal. Install the middle plate. (Make the indicator lamp through middle plate hold.) Close the diffuser. (Fasten with the bottom case). Connect with the AC power.