A sequencer fires notes at the VCO and gates at the envelope. The drone becomes a melody that plays on its own while you tweak.
A drone is still boring. Let us add a sequencer.
The SEQ8 has 8 steps. Each step holds one pitch (Row 1) and one gate state. Wire it up and it plays a melody on its own while you tweak the rest.
Three cables: Clock -> SEQ8 CLK drives it, SEQ8 ROW1 -> VCO V/Oct sends pitch, SEQ8 GATE -> ADSR GATE fires the envelope on each step.
Tip
The clock tells the sequencer when to advance. The sequencer tells the VCO what pitch and the envelope when to fire.