To start using it simply add a reference to Bigfoot.css on your page and that's it.
I also created an alternative CSS stylesheet, Bigfoot_Module.css, which would be referenced instead of Bigfoot.css. It contains all of the same classes and styles, except they are only applied to the element in your page named bfbox.
Download the bigfootCSS sample for a look at how to put it together. You can also view it live hereFor a complete list of what's included and how to use it click here