The screen shot you posted is the logic flow of the horn and bell sounds from the sound editing pane.
DO NOT MESS WITH THIS UNLESS YOU ABSOLUTELY KNOW EXACTLY WHAT YOU ARE DOING!
As Alvin pointed out, on LS5's, the horn selection is done via CV163 and the bell is done via CV164. The complete text description of the sound file will list the horn and bell choices.
I find it easiest to directly program CV163 and/or 164 to select the appropriate horn and bell. You DO NOT have to worry about CV's 31 and 32 when doing this, because CV's 163 and 164 are not "indexed" CVs. So put your engine on the track, use Ops Mode programming (programming on the main) and change horns/bells to your heart's content.
If you really want to do it via the LokProgrammer, the horn/bell selection is done on the Sound Slot pane, in the sub-window right above the actual sound slot listing. But honestly, directly programming CV's 163 and 164 is pretty easy.
John C.