You want to start by determining what kind of charms and the size of the necklace. Most necklaces are about 16-20". If you wanted to make a choker or a bracelet, then measure out a smaller piece of cable chain. Using a ruler makes it easy to measure and later on to add the charms evenly. Using chain nose pliers and side cutters, you want to cut a jump ring and attach to the trigger clasp and then close the end with the pliers. Take the chain and center it on a ruler, find the middle and that's where you will add the first charm. That makes it easy to count out in between charms to make them even. Use side cutters and pliers to open and close the rings to attach the charms.