The double crochet (abbreviated dc) is one of the most common stitches. It is twice as tall as a single crochet (sc). This stitch creates a fairly solid but not stiff fabric.
How to make the double crochet (dc)
Yarn over your hook, insert hook in the specified stitch, yarn over, pull through the stitch, yarn over and pull through 2 loops, yarn over again and pull through remaining 2 loops .