1. Fix the grey outer case of the device to the wall using the three points available. Before mounting, please ensure that the screws used do not prevent the device from closing when the body is in the case (the head of the screws must have a low profile). Note where the electrical / ethernet cables run if they are embedded in the wall.
2. Insert the body of the device into the outer case, ensuring the top fits snugly inside.
3. Once the top is in, push the rest of the body inside the outer case, and fix it shut using a single screw on the back.