Do you mean 'where are the links to fluid grid based CSS layouts' within Dreamweaver?
File > New - Choose Fluid Grid Layout from the left hand side selector and define your settings for all 3 devices on your right.
This video, compiled by one of our senior members David Powers should walk you through: http://www.video2brain.com/en/videos-13533.htm
I think Scott has the same question I do.
I'd like a link to the section in the real Help manual.
Coming from the "Product Help" at the homepage, to the Dreamweaver Help section, the "What's New" category attracted my attention, since the Fluid Grid Layout is a new feature (or at least revamped). But all I find here are introducing video's. I need to dig into the nitty-gritty. And the fragile built-in Help system for Dreamweaver CS6 is "missing" again (so it says, of course, as always...)
I bet I'll find another entry somewhere, but these properly linked bulleted entries could have helped a lot.
Apart from what's already there on the document, you can have a look at these links. We will soon be adding more info on fluid grid layouts.