The first button turns on/off a series of lights in the kitchen. The second button turns on/off several lights in the garden. And the third button causes a click sound in the ceiling above the dining area. So, I gathered it's a yet-unused button.
I was wondering where should I look to hook up a new lightbulb or a new standing lamp, etc. (or if there are any suitable light fixtures for it. I have no idea where to look for.)