heart chain 
 a lobster clasp and extension chain
 3mm rings
 6mm connector settings and 4mm pendant

Ultra simple assembly:

Start by measuring your wrist, then subtract the value of the set connector. Divide the value by 2 to get the measurement of the chains.

Cut the 2 pieces of chain. If your measurement doesn't perfectly align with the positioning of the hearts, reduce the length of one heart, the extension chain will complete the size of the bracelet.

Then connect the chains on each side of the set connector with 3mm rings.

To finish, cut a piece of extension chain about 3cm long, then connect it with a 3mm ring to one end of the bracelet. To beautifully finish the bracelet, place a small setting at the end of the extension chain. 

On the other side, place the clasp with a 3mm ring.

And there you go! Beautiful creation!