I have been working on this project for about 2 weeks now, and is also a part of learning the engine for a competition I am entering with some of the guys that are on my uni course. (That competition is Off The Map for anybody interested, and there's a link to the project page here.)
So far with the Underwater Station, I have taken the concept art and broken it down into a list of required assets, and completed block out on most of these assets. A breakdown of the assets listed here.
Here are a few screens of how the environment is currently looking