Do you write the intro paragraph first? or after you write the rest of the paper?

This sounds like a stupid question. I assure you it's not.

Intro first. Otherwise, I have no idea what order to put things in.

it's fun to just sit down and free write for an hour or two, then paragraph, edit and Finaly write the intro. You wind up with a lot of crap, but the stuff that you do have sets the tone for the rest of it. Eh, but then, i'm an engineer, don't listen to me about writing.
:-D

You can always reorder your other paragraphs later, but I learned once that writing the intro last can make it easier to write, and actually better quality. I tried it, and I've found that it works for me. Try it out. It may help. Cut and paste is there to switch things around later.