I started the cat hammock using polyester craft cord. Using the hook size recommended on the label (which is smaller than my test swatches), I made a chain the length I needed for the narrow side of the mat. (Don’t do this, chain length is drastically different than the length after a couple rows. I should have swatched (ironic), obtained gauge and done a chain based on the calculations.) I did my first row of single crochet stitches in the back loop of the chain. There are many ways to insert the hook in a chain for crochet, this is my favorite and uses the bump-like loop on the back of the v-like chain. It makes a very symmetric first row.