Lower the jack fully and remove it. Replace the hub cap, making sure you carefully align the tire valve with its hole in the hub cap. Tap the hub cap in place evenly with the heel of your hand. Finally, restow the jack and the rest of the tools, remove and store the chock from the wheel, and place the flat tire in the trunk. In general, two of the tires on your car drive the car and the other two simply roll and bear weight.
Older cars use the rear tires for driving and the front for steering.
Newer cars use the front tires for driving and steering. In either case, the driving tires wear faster than the passive tires. If you periodically change the front tires for the back tires the whole set will last a little longer. Also, this changing, or rotation, allows you to check the tires for early signs of defects. They wear much faster and less evenly than larger tires.