There are 3 Lights per pack.  Each lamp is 'powered' with a 0.75mm fiber and comes with 3 foot of 0.75mm fiber attached to it.

The Industrial Building lamp fits into the wall of a building above the door.  We recommend placing it about 1/2" above the top of a door.  

It's size:  It is designed to stick 7/32" out from the wall and coming 1/4" down from the point of exit from the wall.

To mount, drill a 3/64" hole in the side of your building.

To change the ambiance / color, add a drop of translucent paint to either end of the fiber.  If you add it to the end of the fiber that is inserted into the Lamplighter, then make sure the paint is dry prior to inserting the fiber into the Lamplighter box.  See the video on how to do this.  To create an old world look, I use the Tamiya X-26 Orange Translucent paint, however, you may use whatever paint you like or even a colored marker.