Well, I just added a whole lot of distant lights, one for each plane in the room I think. I also added a spotlight, but I went a little overboard trying to figure it out. Apparently, the room comes with a set of lights and cameras which are switched off in, eye icon shut, when loading the environment. They do, however, show up in the renders. I still don't really know what I am doing. My current level is that of trying to get models not to float in thin air or clip unplanned into other figures of obstacles. Advanced camera, texture, lightning and render settings is way ahead of me. I have experienced a little bit with render settings trying to get iray renders to render faster without loosing much of the quality. Although, this last set is 1x1 899x899 pixels with the majority of the renders having a render max samples of 5000. Some of them have only 2000, but the quality didn't degrade too much. I am probably going to render some widescreen pictures later on, when I have some experience.
I bought the poses as well, they have been really helpful in finding nice positions a little bit quicker.