Does anyone know of a tutorial or a demo that explains the different settings for creating fog in a scene?

I can create a pretty basic fog, but I'd like to create rolling fog for a scene that features cloudy steam. I could probably use some 2D planes but then I wouldn't learn more about Carrara, would I? ;)
Thanks in advance!

P.S. -
I really like the forum here. I feel like I can ask questions and I get real feedback and meaty info. Thanks so much!

For thick, rolling fog, I have used the volumetric clouds. Just scale out the cloud into a flatter rectangle.

I honestly hadn't considered using volumetric clouds until you mentioned it, tkane18. That's a good idea.

One thing I want to avoid was a flat rectangle of fog because at the angle I have the camera the fog edge seems very sharp. I thought that some puffy, cottony fog might help out with that.