Apple Logic Pro /LogicExpress Discussion

I have being trying to use the Stradivari solo violin from garritan
with logic, but up until now i haven't being successful in doing so.
-which of the four versions that come with the violin should i use? 
-should i use them all simultaneously and if so, how?

I'm not talking about the various techniques because they, a would
say, are well explained.

thank you all