there are three (basic) ways to attach rickrack--
some people stitch straight down the center...
some people catch the tip of each upper bend.
some times half is caught in a seam and only half shows.
just depends on your project, your likes/dislikes and how much work you want to do.
when stitched down the center the (tips) can curl at times.
when stitching each tip it can be more time consuming-but no curling possilbe.
when putting in seams probably the easiest application