Cut your chain into 2 equal lengths
Take one of your chain pieces. Using a jump ring, attach it to your earring backing. At this point you will need to check the sizing to leave enough chain to dangle under your ear lobe.
Once sized, open the loop on your earring post and connect a length of chain to secure.
Close the jump ring.
Determine how long you want your Swarovski drop to dangle.
Trim chain if needed, and attach Swarovski briolette to the chain using jump rings.
Repeat for your second earring.