I have an air conditioner unit which passes through the wall of my home. It measures approx. 31" x 24" x 7" on the inside wall. I would like to box it in and cover the front with shutters. The wall that the unit is in is approx. 80" long and I would like the box to be approx. 70" long so that the wall and box look balanced. Any assistance as to plans, wood to use etc. would be most appreciated as I am very new home owner and do not have much experience in this kind of work.