Rosette and Rosette 2 is a picture of the old Rosette light fixture. You can see where the hot and neutral wire attach. The cord in the center was for a piece of cord that would hang down and the lampholder would hang off of it. Sorry that I don't have a complete picture. I was lucky to salvage this out of an old building before it all got thrown out.
The Knob and Tube would hook up on the outside screw terminals, hot on one side and neutral on the other. Then you would plug something in to the socket.