1) Main Frame - 2 matching interlocking pieces (thickness = 4 pieces glued cardboard) that form the "X shape" skeleton for seat and back support. A notch (approximately 1" wide) is cut in each piece of the skeleton at the intersection of the back and seat to facilitate joining the pieces together. Locate the first notch at the top of frame piece #1 and extend it down to the exact middle of the frame. Locate the second notch at the bottom of frame piece #2 and extend it up to the exact middle of the frame. Then slide the two pieces together at the notches to create the frame skeleton.
2) Skeletal support for additional strength of the seating area as shown in photos.
3) Seat and Back - thickness = 2 pieces glued cardboard.
4) Chair Trim - for additional support and appearance as shown in the photos.
Finally, while I cannot give a definitive weight rating. I can attest that the chair shown in the photos supports a 180 pound adult with no visible signs of structural stress.