To mount your Lyric on the wall, first remove your old thermostat from the wall and ensure that you have recorded your current wiring configuration. You can find directions for safely doing so [here]. Next, decide if you wish to use the trim ring to cover blemishes on the wall left by the old thermostat. If you do, align the screw holes and snap the trim ring and wallplate together. Now you're ready to install the Lyric!