Place the microwave mounting bracket along the wall underneath the cabinet where you plan to install the microwave. Mark in all of the holes on the bracket with a pencil and take the bracket back down.
Drill through each of the holes marked on the wall. Run the stud finder over each hole and place a heavy-duty drywall anchor into each hole that does not fall on a stud.
Place the microwave bracket back on to the wall and line up the holes on the bracket with the drilled holes. Drive one long bolt through each hole to attach the bracket to the wall securely.
Mark a 2 inch-by-2 inch hole in the center of the cabinet along the back edge. Cut out this hole with a hand saw to provide a pass through for the electrical plug.
Place the Maytag MMV4205AAW microwave template on the bottom side of the wall cabinet and mark in the mounting holes as determined by the template. Drill a hole through each marked location.
Lift the Maytag MMV4205AAW microwave at an angle and place it into the wall cabinet with the hook on the back of the microwave. Have a friend hold this in place for the remainder of the installation. Run the electric plug through the opening on the cabinet.
Line up the holes on the top side of the microwave with those drilled through the cabinet bottom and drive one long bolt down through the cabinet into the hole specified on the microwave to secure it firmly to the cabinet's underside. Have your friend push upward on the cabinet to secure a tight hold. Plug the microwave in to use.