If your bail has a closed loop, it's easy to attach it to pendant with a jump ring. Just follow these steps.
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Chain Nose Pliers
For this technique, choose a closed bail, a pendant, and a jump ring.
With your chain nose pliers, open the jump ring.
Attach the pendant to the jump ring.
Attach the bail to the jump ring.
Close the jump ring.
With the bail attached, you can now string your pendant onto cord or a chain.