Use a MIDI keyboard and a MIDI pedal connected to your iOS or macOS device to play with a subset of the famous Jeux dorgues 2 pipe organ sample set of Joseph Basquin.
For more information, please consult the app support page http://polaron.de/JeuxdorgMini/ , the Napo documentation at http://polaron.de/Napo/ and in particular the Napo user manual at http://polaron.de/Napo/manual .