Since the ends of the ropes are covered by the cones, you have a little freedom here to do what you need to do to attach the rope ends to each other securely.
I used a square stitch thread path, exiting the end bead in one rope, sewing through the closest bead in the next rope, and then sewing through the first bead again (similar to the thread path used in step 4 of "Assembly" on p. 65, and shown in photo l). Then I sewed through the beads and made another join nearby, and kept stitching the ropes together until the connection felt secure. You shouldn't need to work very far down the ropes; when you assemble the bracelet and add the cones a little flexibility will help you arrange the ropes so they wind nicely around your wrist.