Items you need:
Jack up the front side of your car and rest the car on a jackstand. Remove the wheel.
Install the baby spare tire with three lug nuts. I like to do this just in case something bad happens.
Jack up the rear of the car and remove the wheel.

Put the front wheel on where the rear wheel goes. Lower the rear of the car.
Remove the baby spare tire from the front, and install the rear wheel.
Jack the car up to remove the jackstand, and lower the car.
Repeat on the other side of the car. That's it!
Note: Be sure to be on a flat surface when doing this. It would be very easy for your car to roll away or fall off the jack/jackstand when it's on two wheels!