You now basically have 2 rough edged pouches.

• With the wrong side out iron the Lining along your chalk marks. Make sure to iron the top of the lining down, with the unfinished edge facing, along it's 1-inch marking as shown above. It will still be pretty floppy but you should be able to see it's boxy shape.

• Iron along the top marked 1-inch of the Outer Bag and then turn it right side out as shown below. 

• Iron the Outer Bag along the chalk marks. It will be able to stand up and hold it's shape.
  

• Cut a 5-inch x 10-inch piece of heavy-duty template plastic and place it snugly in the bottom of the bag. It should fit exactly.
  

• Now slide the Lining inside the Outer Bag. Make sure all the seams line up neatly. The Lining and the Outer Bag should fit perfectly together because of the ironed sides.
  

• Pin the Lining and the Outer Bag together at the top of the bag
  

• Top stitch with a 1/4-inch seam allowance.