trio template

[Aaron]

Hi all,
A favor from some kind soul.
I am notating a trio for oboe, viola and timpiani.

I have the oboe and viola parts completed, and am editing the timp.
now.
I tried to make a score but no matter how hard I try I can't seem to get 
it right.
I think where I am confused is where to put the header file(s) and the 
clefs and midi score blocks.

my lilypond files are called oboe.ly viola.ly and timp.ly

could someone help me with an example (I call it a driver file) score 
with \include "oboe.ly"
\include "viola.ly"

So I can see where everything should go.
Thanks
Aaron