Help with Shinsuke Irie's Cycles OSL toon shader technique

I am trying to replicate the technique used here: https://blender.stackexchange.com/questions/33871/is-there-really-a-way-to-make-a-true-toon-shader-material-in-cycles (First answer, by Mentalist.)

I downloaded the linked file at BlendSwap, but I can’t figure out how to get this to work. I want to use this effect on my own character model, but I can’t find any instructions or documentation on how to use this method anywhere.

Is there anyone here how understands how to do this, and that can help me figure it out?

Thank you in advance, to anyone who can help. : - )