Hi Gred and welcome to the DaniWeb Community. I am going to list every possible way I know of to fix your problem. Solution 1.
In DreamWeavercs3 there are three buttons on the top left hand corner.
this is the name of each button Code,split,design.
All you have to do is click on code and change the CSS that Dreamweaver has set as default for that template. You can change the CSS to your hearts delight. You can easily figure out what CSS is used for the footer,header,side column, and main column by either reading the HTML (or XHTML) and see the CSS class each section uses.
Solution 2.
You can also edit the CSS simply by clicking on the area you want to change which should bring up the CSS used in that section. Now you can bring up the CSS Properties box windows by pushing shift+f11 on a pc. Then you will see a box that says css styles and there will be a button that says all and current. You would want to choose current then you just edit the css via right clicking hit edit and change what you want then hit apply and ok.
Solution 3 ( a bit advanced but it is a solution)
If you want to make 50 pages with the same colors and you plan on using that template just delete the css that was written and create an external css file either by (1. writing your own CSS external Sheet in DreamWeaver and then importing it or (2. the easiest way just right click on any CSS area hit new then a box will pop up and you have the choice of choosing new style sheet or in this document only. Hit new style sheet and you can tell DreamWeaver exactly what you want that new external style sheet to do.
I hope I didn't overload you with info and I hope I helped!