By any chance did you watch this video? How to Knit the Dancing Cable Stitch (English Style)
Reverse stockinette is the other side of stockinette which is knit one row, purl one row, continue alternating knit rows and purl rows. For reverse stockinette the purl side is the right side. For this pattern just cast on 16 stitches as normal and the the reverse stockinette will appear *magically* as you follow the pattern. No special cast on is required. HTH and enjoy!