I have started organizing the tutorials for Dragon age in to a series called Addin Tutorials. Part 2 is now available on this site after a considerable amount of research.

Addin Tutorial Part 2: Level Creation

It covers the basics in creating interior and exterior levels as well as offering solutions to known problems, especially in respect to lighting. The tutorials are aimed at noobies so anybody should be able to follow them. 

Part 1 is available below, it was formally called  "Dragon Age: New Campaign Location Tutorial" but now takes it place as part of of the series covering the creation of addins for new modders. 

Addin Tutorial Part 1: World Editing and Area Creation

Enjoy