I have that sign.
The On/Off switch is on the back. However, once you turn it on, you will probably never have to turn it off again.
Not sure where the sensor is that turns the light on after dark.
In my case - NO way to building mount it where it will get enough sun.
Plus, it is overpriced IMHO.
I would NOT buy a 2nd one.
Probably why they were giving them away just recently with certain purchases.