Best method for attaching hat brim?

Finished knitting the newsboy cap, from and need the best way to sew on the brim. The pattern indicates: Fold brim in half at center knit stitch, OK, mark for center to match center knit stitch on cap, OK, then sew double thickness of straight edge to bound off edge of hat, huh what??! Logically can see by the picture and know that the edge of the reverse stockinette hat will curl under toward the knit side so the top, rt. side of brim will have to be against the curled rt. side of the hat. I suppose pinning will help control this writhing animal but won’t sewing thru 3 layers look awfully messy? Both brim layers on the same side? Even though it will curl under out of sight it could look lumpy. Would pick up stitches and knit the brim, having only one edge to sew but the brim pattern is at a cross direction to the hat. Love a 3 needle bind off - anybody have a 3 needle sew on? Neater joining with a crochet hook? Solutions and ideas welcome. Jean