Build the sections of your project within MovieClips in the Library, or within external swf files if the sections contain a lot of bitmaps or other bandwidth-expensive content.
You can then just load/add/remove the sections from an Array.
Mazoonist has written a good tutorial on the subject, which also covers other important topics such as writing code in external class files (as opposed to frame-scripting), drag'n'drop, Objects, etc... it's a great beginner overview that promotes "proper" development techniques that you can build on.
http://www.actionscript.org/resource...ses/Page1.html