I kept dropping the nipples into it. They became increasingly more difficult to get out again the more spokes you put in.
Thread the nips backwards a couple of turns onto a spare spoke to hold them, as you screw them onto the in-place spoke they unscrew off the holding spoke.
Thread the nips backwards a couple of turns onto a spare spoke to hold them, as you screw them onto the in-place spoke they unscrew off the holding spoke.