Connect the positive and neutral power leads from the 12-volt AC converter to the positive and neutral connection screws on the back of the 12-volt power switch. The positive lead will have a stripe or dotted line on it. Tighten the screws over the bare wires with a screwdriver to ensure a tight connection.
Connect the neutral power lead from the sprinkler valve that you want the switch to control to the neutral output screw on the power switch. This wire usually is white. Tighten the screw over the wire using a screwdriver.
Connect the positive power lead from the sprinkler valve that you want to control to the positive output screw on the power switch. This wire usually is colored or has a stripe along it. Tighten the screw over the wire using a screwdriver.
Plug in the AC adapter into a standard 120-volt outlet.
Turn the power switch to the "on" position to open the valve and run the sprinkler zone. Turn the switch to the "off" position to end the sprinkler cycle.