Most manufacturers offer online installation instructions for over-the-range microwave ovens, like those available on GE's support site by entering the model number. General installation information is available from SFGate and the video installation guide at About.com.
Over-the-range microwave ovens help to free counter space by mounting the microwave to the bottom of the upper cabinet. The process involves using a special mounting bracket to attach the unit. If replacing an older over-the-range unit with a new one, it is sometimes possible to reuse the existing bracket. Because the process involves lifting the microwave while attaching it or removing it, enlisting the help of a friend is essential.
The weight of the microwave makes it essential to ensure the mounting bracket attaches firmly to the wall and cabinet before attaching the microwave. Most manufacturers require the bracket to connect directly to the studs and cabinet. The manufacturer's directions show the exact locations for inserting screws.
The directions also include information concerning clearances above the stove. Ignoring these instructions creates safety hazards. In some instances, it is necessary to modify the cabinet over the range to meet the manufacturer's specifications. Homeowners who are unsure of their ability to complete the installation should consider hiring a professional to complete the task.