Insert the plastic opening tool at an angle into the grill and lift the tab by applying force down and to the left as you are lifting it out of place.

Use your plastic opening tool to remove the right plastic tab blocking the screw mounts behind the device.

The plastic tab is located on a plastic stretch of grill running along the upper half of the back of the device.

You can find the tab looking for a solid fill within the grill. The tab is solid within the slits.