Now that you have all of the tools and materials, we can jump right into the project. Let's cut the fabric to size. We allowed an additional 1/2" on all edges to make seams around the entire perimeter. Using an iron we pleated a small amount (1/4" or 5mm) of the edge inward, and then folded it again (an additional 1/4" or 5mm) - this technique will prevent any unsightly fraying. You can start with a piece of fabric 17" x 19 1/2" (43 x 49cm) and after making seams on all edges, the dimensions should be 16" x 18 1/2" (41 x 47cm).