you can go about it in many ways. Depending on the level of rust you have on the car.
You can get by usually by prepping rusty parts by using a wire brush attachment on the drill. There are several sizes and types that are available at any hardware store; ie. Home Depot, Lowes.
Once you have removed most of the rust you can use the spray cans of rust-converting primer. Just use several layers. A MN car probably would be a more likely candidate for a rust converting primer. I have seen it at auto parts stores, but it is also at hardware stores.
On areas with serious rust getting started, I would use the POR-15. It is more expensive than the spray rust converter, but it does a great job stopping the rust.
If you have areas that are jagged ir have pieces that have come off I would recommend that you cut that section out and tack a new piece of metal in. Or you can always go to a bone yard and look for those parts, ie fenders, sills, door pieces etc and buy the ones that are not rusted.