Each of the different engines have slightly different functions for the encoders but this should give you a list of the most common ones.
You can change them but this will give you a point of reference.
D0/D1 = LFO Rate D2/D3 = Envelope Release D4/D5 = LFO Depth D6/D7 = Menu
D0/D1 = Oscillator Sustain D2/D3 = Envelope Decay D4/D5 = Oscillator Release D6/D7 = Envelope Sustain
D0/D1 = Oscillator Attack D2/D3 = Envelope Depth D4/D5 = Oscillator Decay D6/D7 = Envelope Attack
D0/D1 = ???? D2/D3 = Filter Cutoff D4/D5 = Oscillator Delay D6/D7 = Filter Resonance