Chrysler Sebring sedan 2.7 engine "clattering"

I just bought a 2001 Sebring Sedan with the 2.7 engine.  I am a home mechanic- only worked on my own cars but have never worked on a 2.7.  

I bought it from a small towing company which had picked it up as a donation vehicle and sold it instead of scrapping it.

Here's the little history I have of the car from what they told me:

They thought it had sat and not been driven for at least the previous six months.

The engine was no good because it made a lot of clattering noise when it was started.  They owned it for about four months and would start it occasionally to move it around in their yard.  

They told me the oil pressure light would come on whenever they started it.  

The on-site mechanics told me they suspected the cams but hadn't done any work on the engine because the owner felt he would have to replace the engine and didn't want to mess with it so he put it up for sale.

They started it for me but I had them turn it off right away when they said the oil pressure light was on.  I did not hear any rod-knocking noise or any particular loud clattering, but then the radiator fan was making quite a bit of noise.  The guy who started it said he heard it clattering.


It has been delivered to me and I am not sure what to do or where to start.  Suggestions?

BTW, I have been researching and have familiarized myself with the "sludge" problem found in the 2.7 L engine.  I am wondering if I should start with the timing belt based on reports of the tension spring failing due to low oil pressure.  Here's my problem; I have never had to replace a timing belt before so this would be my first time.  I'm not sure how or where to begin so I need basic and clear directives.
Thanks in advance.