SharePoint 2007 Help

For my new job I have to build a website (for external viewing) with SharePoint 2007 and SharePoint Designer. I've got it installed on one of our servers and I'm just having some trouble getting getting things to work the way I want.

I've created a new website ../pages/default.aspx

I want to use a custom master page to use for all the pages on this site that doesn't contain all the navigation to administration functions, but I guess I need some page that does have all that stuff so I can maintain the site. How do I set master pages for some of the pages in the site, but also keep a content management page so I can maintain the site through a web interface?

Also when I try to create new webpages it wants to put them in a sub directory (../pages/something/...). Am I missing something obvious about how to make a new page ../pages/newpage.aspx?

For someone who is used to building all his sites in jEdit (with PHP....) this is somewhat confusing. Thanks!