I used an electronic stud/ac wire finder to check the area. Then I used a Rotozip tool set to just cut through the 1/16 inch luan and pulled a square section loose from the Styrofoam in the wall. Then I could check for any DC wiring and verify that there was nothing in the foam I had to worry about. Then I cut a matching section from the outside and cut the foam piece out. I drilled a hole in each corner so I knew where to make the outside cuts.
I used an exhaust fan in the space behind the convection/microwave to pull air in from the room and push it out of the vent I installed. I used a vent that was flap type that tipped out when the fan was running. There were a couple of tabs on the outside that turned to hold it in place while in transit. I got it from an RV store.
