Place a dowel in the vise and drill two 3/4-inch diameter holes in each wooden dowel 2 inches from each end.
Cut the nylon rope length in half with the scissors. Make a knot in one rope length 2 inches from the end. Repeat with the other rope length.
Thread both free rope ends in the holes in one dowel and slide the dowel to the knots. Make knots with the ropes directly above the dowel.
Knot the ropes 10 inches above the previous knots. Thread and slide another dowel to the knots. Make knots with the ropes directly above the dowel. Repeat this step until all dowels have been attached to the rope ladder.
Tie the free top rope ladder ends to one end of the top bunk bed with square knots, which don't loosen when you pull on them. Cut off excess rope ends with the scissors.