This can be made any size, I used curtain lining as the backing fabric, cut 2 pieces about 15 inch by about 36 inch.

I embroidered a design on both pieces, not too near the top
Cut several 3inch strips of plastic and sew bias on the top of the strips. Mark lines on the backing fabric and arrange the plastic strips edge to edge and pin in place. Sew folded bias to the bottom of each strip.
Baste along the side edges near the edge (binding will cover this) I sewed lines from top to bottom through the plastic to make pockets. I did this seperately on both pieces but this could be done when the two pocket pieces are put together back to back. Then bind the edges. I hope this is clear. Should you require any further infirmation please do not hesitate to ask. G

I find that putting a folded sheet of paper under one side of the foot make sewing on vinyl easy. G