Want to apply to DMD program - what should I have in my portfolio?

I have an interest in film and game concept art, and also enjoy math and physics, so the DMD program seems perfect for me. I do not have an art instructor who has experience with digital art, which is what I am most interested in and proficient at (so I’m thinking that’s what I’d want to be putting in my portfolio?), and not enough funds to have a portfolio instructor. I feel totally lost in terms of what I should prepare for my portfolio. Can anyone give me some direction?

Thanks!

I want to apply to UPenn DMD program, and I have 0 sport ECs (but more of art/community services ones). Does this matter? How essential are sports to your application? (I do enjoy sports, but I just have been putting more time into art and community service because I am more passionate about that)

Unless you are a recruited athlete, sports are just another EC. A very good EC, but no better and no worse than any other. It is not essential.