Measure and cut fabric the same width as the length of zipper. At short end of interfaced fabric, make a 1 ¾ inch fold toward interfaced wrong side and press; repeat on opposite end.
Cut lining 2 inches longer than the space created between folded edges of outer bag panel. Place and align zipper to edge of folded outer bag panel with right sides together.
Place lining right side facing wrong side of zipper; stitch in place; open zipper and repeat on other side. Trim seams and make notches at folds and corners before final construction and turning over.
With zipper open, line up notches and stitch ½ inch seam along one side; from outer bag panel to lining; stitch the other side, leaving a 5 - 6 inch opening.
At seam allowances, where the lining is stitched to the edge of pressed folds, turn folds downward and hand-sew to corresponding seams. Sew opening in lining shut, turn over and press.