Step 4: Sewing together the plastic bags
Start by "truing" up the pieces, trimming the edges so they are all straight and even.
Position the pieces to make a rectangle big enough to fit your computer on it twice, with a bit extra for a closure flap. Keep about 2 1/2 in on each side for seam allowance.
Sew pieces together by overlapping them on top of each other and sewing with a zig zag stitch