Want area just below (or included in) header area - html file
 

How can you make an html (or other) file that you save in your forums folder, that will automatically be included in the header, or just below the header, on all pages of the forum.

For instance, I want to have a strip directly under the logo area, that I can change at will (i.e. "Editable-Stip.html").

I want to be able to open Editable-Stip.html in Dreamweaver, Lay it out exactly the way that I want it, and save it. Just like a template, the new, edited version will be included, automatically, in the correct location on the page.

I am a newbie, hence the (most likely) quite obvious question.
Thanks in advance.