Ok, we will get it worked out.
Pattern says Front panel
*sk 2 ch, ch2lp in next ch. Rep from * across. Mark 3rd ch-2 sp for “STRAP B,” and mark last ch-2 sp made for “STRAP A.” Mark this as RS
So the last ch2 sp is where you begin Strap A, and yes you do turn then begin RS. Strap B will begin in the 3rd ch2 sp. The straps are started on the top of the front panel, worked to length and then also begin as either right back or left back depending on which strap you are working.
Please let us know if this helps you or if we can clarify further. This is a beautiful dress, one of my favorites. You'll love it! Your yarn choice is gorgeous too!