Full Browser Flash

I know that this topic has been talked about a lot but I still have not had one of my questions answered. My question is how do you make your FBF look like these two examples.


In this one how do the designers make it work for all resolutions, how they are able to use the whole browser and user three different sections for the menu, the content, and the sound?


How do they make it so seemless in the slide to a new section and how do they keep the BG so seemless? And it is full browser with the single bg image.

That is really what I want to understand, how do I use a single large image to fit the browser(at any resolution) edge to edge?

Thanks in advance.