When I did mine I just cut 3 layers of 5" squares (could use any size you want), So you use the 3 layers as one block, you sew all the "blocks" together with a 1/2 inch seam allowance, and then clip the seams in about 1/4 inch (so you leave 1/4 inch unclipped). The clips are about 1/4 inch to 1/2 inch apart. I didn't even sew an x in each block or anything. It was very simple.
Rachel