I dont understand a few things...

First of all, you have a car to have car insurance, and in order to drive your car you have to have insurance. So if you buy your car from someone, do you have to leave it there, get insurance, and then go back and get it?

Also Where do you get your license plates from? Do you just use the ones they were using?

And what kind of paperwork would have to be done? And Where would that paperwork go? I just don't understand how you make a car officialy yours when you buy it from a private seller.

On insurance; drive straight to your insurance company, and don't get pulled over, phone in advance just in case. Actually, you could probably set up your insurance a day in advance or something, not totally sure. Get your license plates from the Department of Licensing, you get a temp plate until the metal plates come in. The previous owner has to sign the title over to you, I don't recall where that happens, as it's been a while since I bought from a private seller, you could almost certainly find out by calling your local DMV though.

I've bought and sold a few cars privately (in Canada) and here's what I've done.

The day before buying the car I phone the insurance compnay with the VIN of the new vehicle. I ask them to have it set up by the next day.

When you do the deal have the seller sign the back of the registration. Don't drive with no plates. Have the seller drop the car off at your home. You take the signed registration to the licensing office and they'll give you plates right away. You'll also need your new insurance poilcy number but you'll get that when you call your insurance company.

In my case I also had to show the licensing office the safety certifiacte and emissions test, as that is the law in Ontario.