Got a Volca Drum recently. Not sure how some features are supposed to work with so little to go on, but the documentation is in multiple languages, ensuring puzzled owners internationally.
Set the Volca Drum to single MIDI channel and played around some in this first week, setting the program and modulating CC with Digitone.
There is a problem with it listening for notes on any channel. Per someone elsewhere, this can be fixed in future firmware, but that problem could be a deal breaker for someone not interested in working around that.