Final day and it’s a fast one!
With the exterior right side out and the interior wrong side out, put your interior into your exterior.
Put the zipper foot on your machine. Remove the free arm from your machine and slide the bag on. Move the pocket out of the way, smash your bag down and place the needle position on the far right. Starting at the bottom panel seam, start sewing right along the existing stitch line.
Sew until you reach the other end of the bag.
Stitch the handle to secure. Repeat this with the same strap and the other side of that panel, be careful to not twist your handle piece. Repeat again with the other handle piece and the other side of your bag.