UPDATE
I think I know where to do it now. There is the "custom missions" button. That's the place right? And I am also guessing that I have to choose the ship option. But when I do, it goes to a black screen, with music. I am able to quit back to the menu. How is this problem fixed?
Really? Wow. I'm really confused now hahaha. After reading the description, I was under the impression that I would be able to play through the single player campaign with any ship. I know that the appearance was one aspect, but it also seemed like ship choice was another. How does one go about changing then? Thanks for your help too.