when I create a site in Dreamweaver to convert to Wordpress, should I create a .php site or an html site? Or does it matter?
Creating a Wordpress site is fairly involved. Here's a link to a video in which Kristin Long of MIGHTYminnow demonstrates this concept. There is also a tutorial series on how to create a Wordpress site with Dreamweaver (although it was created for Dreamweaver CS5, so there will be some changes in the current version). Depending on what you are trying to do, you may need to download the Server Behavior and Database Add On if you are using the latest version of Dreamweaver.
Hope that helps!