This opens a list, from which you can choose the NotePlayer you prefer to
  be used with the selected player.  If you don't want  any first priority,
  just delete the name manually afterwards (you may use Amiga-X).

  If, at a later time, the selected NotePlayer  can't  be  loaded,  APlayer
  will  give  you  a requester where you can choose to stop or make APlayer
  choose a Noteplayer for you.