I don't think you're doing anything wrong. Instead of following these set up rows exactlly, the instructions should have had you work the repeats in a manner similar to that used in this video
. You should be working to one stitch before the gap as demonstrated and then decreasing. The video uses a different decrease but you can follow the pattern for the decrease if you wish.
Row 1: SL 1, K15 ssk, K1 turn or you can do SL 1, K15, K2tog, K1*
Row 2: SL 1, P5, P2 tog, P1 turn