Punch holes on each end of the 1 1/2 inch side making sure all line up as you stack each piece of card stock.
Thread ends of ribbon through each hole. Add a bead or tie a big enough knot on the ribbon end so that it does not slip through the holes and your book falls apart.
You can pull the ribbon either by the knotted/beaded ends or the center so that the pages stack. Wrap ribbon around the book a few times to close it.