How exactly does a roach motel works? how does the roach get inside?

there were no openings in the roach motel, and the directions said nothing about opening the actually motels. it just says to tear them apart from each other and lay them down in your house.

so how does the roach get inside the motel?

and why does the motel smell like chocolate?

maybe he isn’t suppose to go inside just to be around it. Like its just a decor