When you speak or sing into a regular microphone, a magnet moves and creates a current in a coil of wire. The heavy magnets in regular microphones move slowly and can clip off some of the dynamics of the music they capture. Instead of using a slow moving magnet, condenser microphones use two plates that store or discharge electricity based on how they vibrate together or apart and are much more sensitive and responsive. For a condenser mic to work, though, it needs a separate power source, which comes from a special preamplifier.
Unplug your amplifier and pre-amplifier from their wall outlets.
Plug your condenser microphone's XLR cable into an XLR input on your preamplifier. Select an input that is designed for a condenser mic and provides a "phantom power" feed to energize its capacitor.
Plug an audio patch cable into your pre-amplifier's output. Typically, the output will be a one-quarter inch jack.
Plug the patch cable into an input on your amplifier.
Plug the preamplifier and amplifier into their wall outlets. The microphone is now connected.