hey im there too... figuring out whats the best configuration for my daw( studio one ) ... shame on you arturia... very poor instructions...
as far i know u must see which mode u must assing in midi control center , one knob to work on your DAW.. for ableton maybe its easier cause it has a native template.
maybe u can open ableton , select that button (volume) and assign one knob there, if its not working, go again to the MidiControlCenter and try with other option.... im doing this for a while and still dont know exactly what it does any "mode" u can pick.....