I used a punch to punch out the holes along the bottom and then ran the ribbon through.
Just for a little bit of interest I twisted the ribbon once in the middle. Both ends are secured with a thin layer of PVA glue, just to hold them down!
The right hand side of the DPS I have used the same technique, but only on the right hand bottom corner of the photo, which justs adds a bit of continuity across the DPS. See bottom picture.