The device simply plugs into the port below the dash in the driver's footwell area. While plugged in, the device will work to ensure when you turn auto start/stop off, it stays off.
The device has an LED light that can be turned ON to indicate when it's awake and working. To toggle the LED light ON/OFF, press and hold the auto start/stop button on the vehicle until the LED light on the device blinks (~5 seconds). After completing this procedure, be sure to check the state of auto start/stop using the OFF indicator on the auto start/stop switch. Assuming your preference is OFF, you may need to press the auto start/stop button briefly once more.
The device can be plugged or unplugged at any time. However, since it does not make any changes to the vehicle, the device must stay plugged in for your auto start/stop preference to be automatically restored.