How can I automate render 400 videos?

I want to render a looseleaf paper that turns over to reveal it's back side with after effects. I have an animation of the looseleaf floating with text on it already. But for the reverse side, I want to render 400 different versions, each with slightly different text/imagery. How can I make a template where I can 1) insert the 400 different graphics to the back side of the paper. And 2) Render all 400 unique videos into short 5 second clips of the paper flipping over.