How to assign a LAYOUT to a Menu Item per Demo Site?

OK, so we are working with the T3 Quickstart for Joomla! 2.5. I get how to assign a Template Style to a menu item, like below...

t3_blank - Home 1 = http://demo.t3-framework.org/joomla25/index.php/homepage/home-style-1
t3_blank - Home 2 = http://demo.t3-framework.org/joomla25/index.php/homepage/home-style-2

But how did you assign a LAYOUT within the Default Template to the below?

3 Columns = http://demo.t3-framework.org/joomla25/index.php/layouts/3-columns
Left Sidebar + Content = http://demo.t3-framework.org/joomla25/index.php/layouts/left-sidebar-content

and so on.. I can't see where Joomla is calling those LAYOUTS within the Default Template?

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found this..

In T3 framework, each style will use one layout (but please keep in mind that one site use many styles --> so one site can use multiple layouts simultaneously because T3 use multiple styles simultaneously).

So even more confused since the demo site looks like it has several layouts with just one style?