I'm attempting to create an interactive vertical gallery strip

So there are a few things I'm trying to to with this. First, there will be three strips on an array of monitors. This is going to be, essentially, a 1080x5760 monitor. The rightmost monitor will display three strips of movies and images in a 3x3 pattern. For the menu selections with more than 9 items, I want to be able to scroll through the gallery images. Size doesn't really matter, I just wanted to give you some background info. So the stage will be huge, and shared across three monitors.

*What I'm thinking is a varColumnx==true condition for each column on mouseover event listener over a partially transparent arrow field to trigger the object movement by x pixels.

*Would this be better served by invisible buttons that trigger the actions for each column? Then have a larger visible arrow over all three columns that doesn't do anything but look pretty? It'd have less code then.

*How would I make the thumbnails end at the top of the stage and not go beyond when at the last thumbnail on a downscroll, and vice versa?

Then I would just have to figure out the "player" for images and videos playing content from each individual movieclip "thumbnail"

I spent all day yesterday crawling around the web and these forums, but found mostly things for AS2. Why? Not sure.

Btw, I'm a total newb to this, it's for one assignment, and isn't part of the curriculum i'm in, but it's part of the project. Makes no sense.