Turn signals are usually activated by a lever attached to the left side of the steering column, where it is convenient to the left hand. The left hand is the one on which most people wear their wrist watch.
Pulling up or down on the lever makes little lights on the front and back of your vehicle blink. You may have seen this on other vehicles. A light may also blink on your dashboard, and there will probably be a faint clicking or beeping noise which sounds in time with the light. This does not indicate a malfunction of your vehicle, it is simply to let you know that your turn signal is activated.
Pulling up on the lever turns on the right turn signal. Use this if you are going to turn right. Up is the direction of the sky. Right is the direction of the little hand when it is three o'clock.
Pulling down on the lever turns on the left turn signal. Use this if you are going to turn left. Down is the direction of the ground. Left is the direction of the little hand when it is nine o'clock.
If you turn your steering wheel far enough, when you turn it back to straighten out your vehicle, your turn signal will turn off for you. The lever will return to the middle position, the noise will stop, and the blinking lights on the front and back of the car will go out.
If you have completed the turn, or for some reason decide against turning, and the signal is still on, you can turn it off by returning the lever to the middle position.
Turn signals directly benefit people who are not you. It is important to note that you nonetheless indirectly benefit from your use of turn signals.
If you see a light blinking on the rear corner of a vehicle ahead of you, it usually indicates that the driver intends to turn the vehicle in the indicated direction, that is, if the left rear corner light is blinking, the driver will probably soon turn left. You can use this information in various ways. You might slow down or change lanes, if you are behind him, anticipating that he will need to slow down in order to make this turn, and that if you don't slow down, you may run into him, causing damage to your vehicle which it will cost you money either to repair or to pay increased insurance premiums, or both, so that you then may not be able to afford to purchase other things which you desire.
This is the difficult part. Imagine that you are the driver of this other vehicle. Not yourself, but an entirely different person altogether. A person who is preparing to make a left turn, and who is being followed by another vehicle. If you use your turn signal, the driver behind you has a better chance of avoiding a collision with you, as we just discussed. If he collides with you, you will be delayed in reaching your destination, perhaps for a considerable time, and the police may become involved. You don't want that, do you?
Note that the benefits of using turn signals do not necessarily depend on whether or not using turn signals is common practice in your locality. Under normal circumstances, the person who uses turn signals is at an advantage regardless.
A good time to use a turn signal is before you initiate the turn. In fact, you should pull up or down on the lever (whichever is appropriate) as soon as it would be clear to the drivers behind you where it is that you intend to turn. Usually this is before one reaches an intersection, before one applies the brakes to slow down to make the turn.
If you are still unsure of the proper use of turn signals, don't be ashamed to ask a more enlightened driver. It's the only way you'll ever learn!