A branch pendant
 A 4mm set pendant
 Chain
 Oval rings
 A clasp
 From the extension chain

To start, cut 2 pieces of chain about 18cm each for a choker necklace. Adjust the length to your liking.

Then open an oval ring and connect a piece of chain to the pendant. Do the same with the other chain.

In the center of the pendant, you will see a ring; this one is open and will allow you to connect the setting directly without an additional ring. 

To finish, at the ends of the chains, place the carabiner on one side and the extension chain on the other side.

And there you go! Beautiful creation!