 Consult the installation manual to determine the best location to mount the carbon monoxide detector. Keep in mind that this detector can be mounted either on a wall or on the ceiling. With the CO detector facing you, twist the mounting base on the bottom clockwise to separate the detector from the mounting base. Once you have selected the mounting location, drill two pilot holes using the mounting bracket as a guide. For best results, place the holes in the channel on the left and right as close to the center as possible. Mount the CO detector to the mounting plate by locating the detector's alignment hole slightly to the left of the raised alignment notch on the mounting plate. If properly aligned, the detector should fit flush inside the mounting plate. Twist the CO detector clockwise to lock it into place. With the Relye panel in programming mode, press and hold the test button for up to 30 seconds. While pressing the test button, the Relye panel should speak the name of this carbon monoxide detector. When you hear this, you can release the test button. Make sure to subscribe to our YouTube page and click the Show More tab underneath the video where you can view valuable links pertaining to this product, similar how-to videos, and our low-cost, no-contract alarm monitoring services.