I know nothing about repaints.

I have quite a few downloaded models (none of which I know how to insert into FS) and a few of them have repaints, specifically I have the Starship 2000 and a purple repaint for it. I'd like to put it into the sim and make it purple from its default white scheme. How do I do this? I have tried to follow the directions for inserting aircraft, but I cannot get Windows to open in two screens, thus I cannot even get started on a repaint. Any thoughtful ideas out there?