To connect a Master Valve (or Pump Relay) to your RainMachine, connect the common wire to a common terminal, and the other wire to the Zone 1 terminal. (Wiring diagrams included below)
If you have an HD-12/16, you can complete the setup from either the app or the touchscreen of the device. On the touchscreen, go to the Wrench > Zones > Zone 1 > Enable Master Valve.
To setup from the app, go to Zones > Edit Zones > Zone 1 > Enable Master Valve.
Now the Master Valve is ready for use.
Note: The Mini-8 can only be setup from the app.