Step 11: Bag Flap
Make a duct tape rectangle 35cm x 39cm.
This is going to be the flap over the top of the bag. Cut out two corners (about 1 inch square) so the flap will fit between the sides of the frame. Tape this down to the top of the bag.
You can use buckles to secure the flap down, but I'm content with a strip of duct tape. Both will work just fine.