How do I install the Honeywell T4 Pro thermostat with the optional cover plate?

First, turn off power at the breaker box. Separate the Junction Box Adapter from the Cover Plate, then mount the Junction Box Adapter to the wall using the supplied screws without overtightening. Attach the UWP by hanging it on the top hook of the adapter and snapping the bottom in place. Finally, snap the Cover Plate onto the Junction Box Adapter. Make sure the adapter plate is level during installation.