So you are on your way home and all of a sudden your tire blows out. Unfortunately, your cell phone doesn't work because you are out in the middle of nowhere or maybe you don't have coverage for this type of incident. Fortunately, changing out a tire isn't rocket science though it can require some muscle.
1. First off, make sure you pull over to the side of the road as far away from traffic as possible. The further the better because not only is it safer, it will make changing the tire easier. Once you feel that you are in a safe enough situation, get out of the car and get the jack and spare tire. Depending upon your vehicle these can be situated in different places. Also make sure that your car is as level as possible and not on an incline!
2. If you are in a regular car, most likely the spare tire will be located inside of the trunk underneath the lining. The jack may be located along with the spare tire or may have it's own separate container located somewhere in the trunk itself. Some other vehicles may have the spare tire located on the back door such as SUV's and most likely the jack will be located somewhere in the back.
It should be pretty easy to locate the spare tire but the jack may prove a little bit more difficult. If anything, consult the owner's manual that is usually located inside of the glove box. This should tell you where things are located.
3. Once you have the spare tire and jack make your way to the flat tire. Some jacks are different then others in the way that they are setup. Some may be flat while others may have a notch in them that is made specifically to fit along a certain part of the car. You can sometimes find an illustration on a sticker on the jack itself or inside of the owner's manual of the vehicle. Place the jack in the appropriate area, ideally you want it placed on a strong surface such as the road itself.
4. Before you attempt to start to jack the car up you need to loosen the nuts that hold the tire on. Doing this BEFORE you raise the car up makes it a lot easier. However, this is also the hardest part because the nuts can become quite tight after years of driving. Once you have the nuts loose (not off) you can then start to jack the car up.
Hopefully you have something to remove the nuts; some car manufacturers include a tool along with the jack that can remove the nuts. If not, it is always a good idea to carry around a small tool kit in your trunk for emergencies such as this 
5. Once you have the tire completely off of the ground you can then remove the nuts that you already loosened in step 4. Then remove the tire itself and set it aside. Grab the spare tire and place it back on the car and place the nuts back on the tire. Do not tighten them up all the way just yet though, just enough for them to hold the tire flat against the bolts themselves so that the tire does not slant towards/away from you.
6. Lower the car back down until the jack is no longer supporting the weight of the car. Tighten the nuts on the wheel skipping every other nut. Do not tighten them in order, make sure you tighten a nut, skip over one, tighten the next one and repeat until all of them are tight.
7. There you have it! You have successfully replaced a flat tire on your car 
Note: If you happen to be driving on an actual spare tire not just an extra it is advised that you drive at a slower speed. A spare tire is not designed to handle the speeds that a normal spare tire can and it is not designed for long periods of travel. Your best bet is to get the spare tire on the car and make your way to the nearest area that allows you to have a proper tire put on your car.
Most spare tires are designed for speeds of less then 60 mph.
