zionner, there are plenty of files around here to give you a good boot (oh, I mean boost).
Like Volker's tutorial (and files) or nvseal's tutorial or moodflows or any one of a number of helpful people here. Need inspiration? Just check out Seth's work or Moodflow's or TU's or look at some of the things people have done in the public displays on the main Terragen page.
Goof around with it. Just have fun.
Good luck.