Flash Plan Assignment

I am so excited about learning how to make a Flash animation, however, I know next to nothing about Flash! I feel confident though that after watching all the screencasts, I should have a better understanding of what Flash is all about and should (with a little help from my friends and mentors) be able to create what it is I'm dreaming up for my PBL assignment. So here it is, my plan for my Flash assignment, otherwise known as My Flash Plan:
PURPOSE: The purpose of my project is to introduce the Orphan Train Webquest I am creating for my PBL work this semester.
AUDIENCE: The audience I'm targeting is the class I'm creating the webquest for, a group of 5th grade students.

CONTENT, LAYOUT and DESIGN: I'm visualizing an old-fashioned passenger train car moving across the top of the screen (think Splash header), complete with audio of train whistles and engine sounds. I would like each window on the train to be blank, but as the train moves, for different pictures to open in each window. The pictures will be actual photographs of orphans who traveled on the real Orphan Trains. I'm still thinking of the text, if any, that I might want to appear as the train reaches the end of the page, maybe just the title of the webquest and a catchy subtitle, with my name.
So, that's the PLAN! I'm excited to get started, but I'm not sure of how to do that yet! In the meantime, I'm going to look for the photographs I want to include in the project.