How do you build a portfolio on cinematography?

[Crys N]

This is probably a really stupid question but I'm applying to SCAD (Savannah College of Art and Design) for their cinematography and film studies major and I don't really understand how I would build a portfolio on my knowledge of that subject. I mean, I can't include films I have made in a portfolio unless it is an online portfolio and I believe they want a real in-the-flesh portfolio. So I really don't know how to go about it. I've read that they want your portfolio to reflect the courses you will be taking. Like if you are doing traditional art courses your portfolio should reflect that. But I don't know how I am to build a portfolio on films. I want to direct (very far into the future) and I figured SCAD was a good school for the films, of course my options are also open to MICA, NYU and more locally, UNC Wilmington