You will need;
Chain the length of what you want,
Crystals and pearls.
Thread a bead cap and a bead onto a head pin. Cut off part of the pin leaving about 1.5cm. Use round nose pliers to make a loop. Make a few of these.
Tread the charms onto the jump rings. Then tread the whole lot onto the chain in what ever order until you are happy with the thickness.
Attach the clasp using jump rings. Tread another bead onto a head pin and attach next to clasp. This makes the back of the necklace look nice if you are wearing your hair up.