From the instructions provided with package:

Copy and paste the 9 .wav files to your sound directory.
Copy and paste the fpda_boeing_callout.gau to your gauges directory.
Then simply open the panel.cfg file of the aircraft you wish to enhance with altitude callouts.
Insert the following line (replace the xx with the next available gauge number) in the appropriate spot.
gaugeXX=FPDA_Boeing_Callout, 10, 100
See Panel.cfg info.txt for an example using the default b737-400 panel.
The next time you land that aircraft, your co-pilot will keep you posted on the altitude!
This will work in virtually any panel for any aircraft.