Hi Jim,
Cheetah is a great piece of software! I use it primarily for renderings, but the modeling side is also very powerful. I, too, knew nothing about modeling (other than in Sketchup) when I got Cheetah and it has been a really exciting learning curve.
Rendering, for me, has been all about experimenting different things. It can be frustrating at times and I am still only happy with about 25% of my final renderings, but I am starting to get a good grasp of settings that seem to work.
The Cheetah forums are really good! There are a bunch of really experienced guys there who are very helpful. They are located here: http://www.cheetah3d.de/forum/
Welcome to the club here! I think you will really enjoy your time here. Talk about helpful and friendly!