Knowing how to cool an overheated engine is a very important skill that can apply to any licensed driver. Being able to trouble shoot and fix your own overheating issue will save you from having to get help from a stranger or having your car towed to an automotive repair shop.
If your car is overheating and you see white smoke coming from under your hood it is not smoke but steam that is coming from your engine overheating. An overheating engine can happen when your car does not get enough coolant to cool the motor. The first thing you want to do is turn off your air conditioning if it is on. The pump to the AC unit draws power from the motor which in turn makes the motor work harder. You can also turn on your heater to its hottest setting and run the fan on high. This draws heat from the engine block and will help keep the motor cooler. You will need to pull over to a safe spot like a parking lot or to the side of the road so you can identify the problem. Turn off the car and open the hood to the engine compartment. If the hood is to hot to touch give it time to cool down before opening. Once the hood is open you will want to let the engine cool down before you remove the radiator cap.
Sometimes it can take as much as an hour for the motor to be completely cool. You will need to check the level of the radiator fluid in your radiator by removing the cap. If it is low then you can refill with coolant and water if available. If you only have access to water you can fill the radiator and put the cap back on. Also check the coolant reservoir to make sure it is full. It is a good idea to also check the hoses for leaks or cracks. If you have a broken hose then most likely you will be calling a tow truck. You do not want to drive your car if there is coolant leaking from the system. Your motor will overheat and chances are you will ruin it. If no leaks are found start your car up and keep an eye on the temperature gauge. If the needle goes back up to the red area, turn the car off.