If you've just purchased the CSS upgrade and are having trouble figuring out where to begin, I've put up a step by step tutorial in my blog. http://galefraney.wordpress.com/2007/05/13/getting-started-with-css-upgrade/
I struggled for several days trying to figure out how the darn thing worked, and although I visited the Forum, nothing seemed to answer my very basic questions. After a few days of reading and searching the internet, I finally figured out a few basics which might be useful for those who are just starting from scratch. I hope you find the link useful. :-)