I didn’t manage to properly sync my Volcas and VCV, so I just play them as sound modules. Same interface suggested by @ale47p + the native VCV CV-MIDI module. If you have a Volca FM, don’t miss the unofficial 1.09 firmware. Together with the free Dexed synth and the native VCV CV-CC module, it allows you to modulate all the parameters of the 6 oscillators.