The cowl is worked flat. It is 11SC (single crochet) stitches wide, it does not use SL (slip) stitches. The ch1 at the end of each row is like a little step up so when you FLO SC across the row you get a nice clean edge, when you start the next row that ch1 is not an extra stitch, it just helps keep the edge from rolling over on itself.
Begin: CH 12
Row 1: SC in second stitch from hook, SC to end of row <11 STS>, CH1, turn work.
Row 2: FLO SC to end of row <11 STS>, CH1, turn work. Repeat this step until you have about 3 feet of yarn left.
Finishing: Bind off and sew short edges together.