ac1126, keep your fingers off the metal band until the probe is inserted.
The salt water should be pretty salty. You only need a small amount-- a fourth of a cup or so.
The slat water and ther metal band on he stylet complete the circuit, so if you keep your moistened finger off until the probe is in place, the beeping should occur according to instructions.
It's a real pain though. Some have figured it out after some practice, but I found it to be a huge waste of time.