Maybe these two photos will help.
The yellow arrow points to how the BACK of the flap is hog-ringed. The red arrow points to where the INSIDE of the flap is hog-ringed.
The inside of the flap should have a listing wire in it that hog-ringed to the springs, then the flap is flipped over that ledge in the seat frame and hog-ringed to about the same place but on the outside back.
