It looks to me like they are just fabric scraps cut and folded like bias tape. Since they are no-sew, they must be glued together. I would use a permanent fabric glue such as Aleen's Fabric Fushion which comes in small easy to use tubes. The tips of the tubes are very fine so you can easily place the glue right where you need it. If you have a Clover mini iron you can place a small piece of Teflon ironing sheet over the glued area to apply heat and the glue will set up almost immediately, otherwise you'll have to hold the pieces together until the glue dries. Looks like a fun project, good luck!