Thread the beading wires on one end of the necklace through a crimp tube, a closure part (here an extender chain with closed rings), and then back through crimp tube. Flatten crimp tube with large crimping pliers. Use the crimping pliers to "fold" the crimp tube in half and flatten again. Push several beads over the wire tails before trimming away the excess beading wires. Repeat the process with the beading wires at the other end.