Installing an air conditioner for windows is best done with two people. These units can be heavy and uncomfortable, and the last thing you want is for the AC unit to fall through the window or the floor, ask an assistant to place the air conditioner.
Step 1: With the bottom sheet of the window up, center and insert the air conditioner into the window. Keep it balanced when dragging the flange on the bottom of the box to the outer edge of the window sill. Then lower the lower leaf of the window until it sits in the air conditioner and firmly on the upper flange.