Inspect the area where you plan to install the microwave. An outlet should be within reach of the power cord, and the appliance needs enough room to fit safely in the space. A few inches of space should be at the back, top and sides for air to circulate.
Call an electrician if there is no power source within reach of the cable. Most major manufacturers advise against using an extension cord to power the appliance because of the risk of overloading the wiring. If possible, consider cutting a hole through the cabinet or nook to reach an outlet.
Contact the manufacturer to see if there is a trim kit available for the edge of the oven. These plastic parts frame the front of the oven, making it appear as though it is fully enclosed. Trim kits are usually vented to allow air to pass through.
Hook up the power and place the microwave in the cabinet or other opening of suitable size so the door is flush with the front edge. Avoid bunching up the cable at the back as much as possible. Open and close the door to ensure it has enough room to swing.