Shut off the breaker controlling the AC outlet leading to the junction box where the fan will be mounted.
Unscrew the cover plate over the junction box with the appropriate screwdriver. Pull the three wires down.
Unscrew the wire nuts covering the bare copper wire. Alternately, use the stripper tool to remove 1/2 inch of insulation from the ends of each wire.
Slide the three wires into the appropriate indicated slots in the plug on the low voltage transformer. Tighten the small set screws on the transformer to secure the wires.
Mount the fan according to the manufacturer's directions. Turn the breaker back on at the electrical panel. Flip the switch wired to the fan's junction box to test.