Sharp install manual.
-There is a large metal mounting bracket that is secured to the wall.
-Inside the upper cabinet above the microwave there should be 2 screws near the front of the microwave - one on the left and one on the right. See step 8 on page 7 of the install manual. The microwave's case is set up for 2 mounting points to the upper cabinet, although, as others have stated, there may be additional screws that are securing the microwave's case to the upper cabinet as well.
-Removing the grills from the bottom of the microwave will reveal 2 long bolts that go up at a diagonal that hold the microwave to the metal mounting bracket.
