Ask to Save MIDI - controls wether the editor will ask to save unsaved MIDI file on exit.
Auto Save Options - if checked, automatically saves options on exit.
Note Naming - controls, whether note 'si' will appear as H or B letter.
MIDI Output Device drop down lists allow you to select the corresponding device from the lists of available devices. By default MIDI Mapper is selected. You can change it if you want to use other device or driver.