Beads are threaded onto the wire before starting. Once you begin crocheting with the wire, simply crochet, push one or more beads forward and crochet after them, push some more beads forward and crochet after them. Continue until you have about 1 1/2 the length you require.
Crochet two or more strands, as above. Then twist the strands together, quite tightly, until they form a single band. Thread wire through a bead cap/cone, and form a loop around the chosen clasp.
Any beads can be used. This is a fabulous way to use up odds and ends – left over beads from other projects!