How tell LaTeX where to find LP?

[Claus Rogge]

I tried to copy the "example of a musicological document" from chapter
13 in the documentation into LaTeX (I use TexShop 2.09d, if that helps)
and get an error: Latex does not know what to do with the command
lilypond.
I tried searching the archives but did not understand the postings (yes,
I apparently am that stupid). Is there a simple solution like an
environment variable that has to be set (where?) - or is it too
complicated for a dummy like me?
-- 
My new CD "Know Greed":
http://cdbaby.com/cd/rogge