Chris,
> I'm just looking for some help as to how I should lay it out (where my desk should go) and where I should start with some future treatment. <
You already got some good links. There are many articles on the RealTraps site that explain this stuff in detail, and
How to Set Up a Room is a good place to start. There's also a video version of that article that explains even more.
To answer your main question, you want the loudspeakers to fire the longer way down the room. Click
HERE to see a graph that shows the response both ways in a room similar to yours, and you can clearly see the difference in orientations.
--Ethan