There are hundreorials online like the following outdated one (unless you're using the old version):
Creating your first website – Part 1: Setting up your site and project files (Adobe CS3/4):
Dreamweaver Basics: http://www.merciwebd...averbasics.html
Free New Adobe CS5 Tutorials: 17+ Hours of Online Video Training: http://prodesigntool...5-products.html
How to download and edit a template with Dreamweaver CS3 (Video)
How to Create a Clickable Image Map With Dreamweaver: http://www.ehow.com/...able-image.html
Insert client-side image maps: http://help.adobe.co...8d65-7c13a.html
Dreamweaver (DW) requires you to set up a Projects folder for your web site files. It will help you keep track of the files you make and use. It will warn you when you are about to use a file outside the Projects folder and ask if you want to move/copy file to Projects folder.
Editing in Visual Mode is the worse thing anyone can do. Every Preview in that mode actually changes any editing that may have been made in Code Source View. All previewing should always be done in your browser. If it doesn't work in your browser, it's because the file paths are incorrect and/or your external CSS file has not been linked or not linked correctly on your web pages.
Depending on your options set, DW may have even used the full path for links to pages/images which will not work when you upload your files to your web site. This is because the full path used is a path on your own hard drive and will not work for online pages.
All files MUST maintain the same exact relationship online as you made them on your hard drive. That's why a Projects folder is recommended so that all folders/files will always maintain the correct relative path to each other as you'll use online.