How to change a flat tire

Get somewhere safe and level, block a wheel so the car can't roll, loosen the lug nuts before you jack the car up, and tighten them in a star pattern. Then check the spare's pressure and get to a tire shop.

Do it like this

1. Pull over somewhere flat, as far from traffic as you can. A parking lot or side street is safest; on a highway, take the next exit if you can. Hazards on, park, parking brake on.
2. Set reflective triangles behind the car, about 100 feet back on fast roads.
3. Block the wheel on the opposite corner from the flat with a wheel wedge. A large rock works if you don't have one.
4. Loosen each lug nut, turning counterclockwise, while the tire is still on the ground. Don't take them off yet.
5. Put the jack at the exact spot your owner's manual shows, and raise the car until the flat is a few inches off the ground.
6. Remove the nuts and the flat, and put the spare on. Snug the nuts in a star pattern, going to the nut across from the one you just did instead of the one next to it.
7. Lower the car and tighten the nuts firmly in the same pattern.
8. Check the spare's pressure with your gauge. Spares sit unused and often lose air, and most compact spares take about 60 psi, much more than your other tires.
9. Drive a few miles, then tighten the lug nuts one more time. At the tire shop, ask them to tighten the nuts to your car's torque spec (it's in the owner's manual). AAA says the final tightening should be done with a calibrated torque wrench, not an impact wrench.