I used 1" foam board instead of Styrofoam as its easier to handle and doesnt make the white things everywhere. I cut a frame to fit snuggly inside the window about 6" wide then used the peice cut out of the center to cut into strips for the boards. On back I used some old used thick mil plastic from painting and cut it like broken glass then finished the back with black landscape fabric. Let's some light come through and great with a bulb behind it at night. You'll need foamboard, foamboard adhesive, plastic and landscape fabric. To keep them in the windows I cut a few wedges of wood to stick around the outside. See windows below.