The toolset for Dragon Age is a large program with a lot of options and a lot of interdependency.
You can do level design in the same window with the dialogue editor so you have full control over all aspects of your modification.
With so much power comes (responsibility.. sorry, couldn't resist) a steep learning curve to understand all the aspects you need for a specific task. There is a wiki with some good starter tutorials, there are also some video tutorials for those of us who learn better the audio visual way (like me). But there are nor advanced tutorials there or anywhere else but you can ask questions in the forum at the Bioware Social Network.
It took me about half a year to get my bearings with the toolset and there are still parts of it that I do not understand at all. But for the most parts of my mod I know where to look and what to change.
The toolset has some bugs like every piece of software, some of them easy to find and to avoid, others can really creep up on you and you have to redo a lot of work. I might do some posts on aspects of the toolset or dragon age modding in general in the future, not sure yet.
In relation to my own mod, I have about 10 areas planned and maybe a hundred npcs. The easiest part are the visuals because I mostly use original designs from the game and be able to change them to my liking without much hassle with the morph and the creature editors inside the toolset. The level editor is a little bit more complicated but I don't need it that much with using original content. Rearranging some furniture or pushing a wall to the side is easier than building the level from scratch but even that is not that much of a deal with a little bit of practice once you are familiar with the usage of the tile sets and the difference between the camera modes(area vs. level editor).
The hard part is breathing life into those visuals and make them move around but I will get the hang of it in time, hopefully.