For this stitch, chain any number of stitches
1: Work one row of Single Crochet. Chain 1, turn
2: Single Crochet into the back loop of every stitch. Chain 1, turn.
Repeat from 2 for pattern.
In the picture below, the front loop of the stitch is pink, and the back loop is blue. You want to insert your crochet hook under the blue loop of each stitch.