Tip: Pins will leave small holes in the oilcloth, so use binder clips instead to avoid this.
First, remove the pins and pattern from the cosmetic bag piece. On the short ends, fold the edge over a ½” and press with your fingers to make a crease. With the zipper open, center it evenly on one end and pin. Stitch along the fold line using a zipper foot.
Take the other end, pin, and stitch to the zipper.