KORG PA4X 76 - Manual (Page 479)

Making new sounds with Sampling |475
assigning the new Sound or Drum Kit to a
part/track
The new Sounds or Drum Kits are contained in the User banks. Assign them
to the Keyboard, Accompaniment or Song tracks, as you would do with
any other Sound or Drum Kit. Drum Kits are better suited for the Drum or
Percussion track.
When done, save the Sound set (Keyboard Set, SongBook Entry, Style
Settings, MIDI Song) to preserve your editing.