Check this links, it might help you: http://webdesign.about.com/od/dreamweaverhowtos/ss/aadwcss.htm http://webdesign.about.com/od/dreamweaverhowtos/ig/Add-Styles-with-Dreamweaver/
<head> <link href="CSS/style.css" rel="stylesheet" type="text/css" media="screen" /> </head> This code is connected to HTML CODE or you can watch tutorial on youtube or any channel available.
Simple, don't... pitch that fat bloated pile of manure on the compost heap where it belongs and work with the code in any of the several dozen free plaintext editors. There is NOTHING of value DW can do except teach you the wrong way of building sites. Particularly since your question pretty much means by default you are likely not using "just in code view".