Sorry I don't use it (but understand it works OK) but there are videos at the site. Try with a simple smaller terrain section. Also Valiarchitects has Instant Terrain that I have used. The point of Instant Terrain is to provide an even and regular terrain geometry from your model, because sometimes that is needed to have InstantRoad work. Try with a portion of your work (in a test file). You can get help by contacting Valiarchitects (Chuck) if you make a try and refine your questions.
