Rusty Rod has about covered it.
If your not experienced with body work get a book or find a friend who is. You can get body dollies and hammers pretty cheap. Take your time and try to get as much of a dent out as possible so you use as little filler as possible. And don't body fill over rust,remove it and add patch panels where needed. You will not be happy with the results (usually cracking)and only have to do it all over and have twice as much rust and rot.
A truck in progress and covered in primer is a piece of art.
