Copy all the .bak and .age3Yscn files into your document folder \My Games\Age of Empires 3\Scenario folder.
Copy the entire folder "Pirate Sound" into Microsoft Games\Age of Empires III\Sound folder
First Scenerrio: This is an intro about a ship being attack and the hero left on a deserted island.
Second Sceneria: Escape from island. However this is unfinished. Anybody care to continue?
You are free to use the first scenario as an intro to your own scenario.