Stand on a step stool to look inside the cabinets over the installation area for your microwave. Check the available vents. Many wall-mounted microwaves can hook up to a vent or work with a filter to recirculate the air.
Use the supplied screws that came with the microwave to connect the metal damper plate to the microwave's vent opening on top for the cabinet vent. If you are not using a cabinet vent, screw on the filter supplied with the microwave to the top of the appliance.
Press the mounting bracket against the wall, centered under the cabinet, so the bracket touches the bottom of the cabinet. Mark the wall with a pencil through each bracket hole then drill a pilot hole through each mark.
Screw in the bolts supplied with the microwave through the bracket holes into the wall.
Lift the appliance to the bracket so there is a slight gap at the bottom of the cabinet. Mark the bottom of the cabinet with the pencil to match the screw sockets on the microwave surface. Make a separate mark near the back of the cabinet bottom to cut a hole for the electrical cord.
Drill holes at the pencil marks for the screws that connect the cabinet to the microwave. Use a separate bore bit to cut a hole in the bottom of the cabinet large enough for the electrical cord to insert into the cabinet.
Hang the back edge of the microwave onto the bracket bolted to the wall. Have an assistant support the appliance from below as you guide the top of the microwave under the vent in the cabinet. Skip this step if you are using a circulating filter attached to the microwave noted in Step 2.
Push the electrical plug for the microwave through the larger hole and into the cabinet.
Insert screws through the supplied washers and tighten each screw through the interior cabinet bottom into the microwave underneath. Your helper can now let go of the appliance.
Connect the electrical cord to the power socket inside the cabinet.