The 2 small plywood panels that support the rear ends of the front wings are easy to make and install. Just remember to include enough material at its inner edge, to insert into the slot on the wood frame. It is fixed to this slot with 3 no.8 screws inserted at an angle of approximately 45 degrees. It is also screwed against the front of the door-step with a couple of no.10 screws and the thin strip under the doorstep screws to its outer corner with a no.6 screw. An alloy panel fits over this plywood (visible in one of the above photos).