What is a one-sentence summary of the following article?
A clicker is a hand-held dog training device that, when pushed, makes a "click" sound. When your dog performs the desired behavior, you press the device. Then, you reward the dog with a treat. Your pet will learn to associate that behavior with rewards. Pressing the clicker when the dog performs a behavior is much more effective than saying "Good dog." This is because a clicker has a distinctive and unchanging sound and the dog hears the sound at the exact moment a behavior occurs. Prepare several small pieces of a highly desirable treat, such as bits of hotdog or boiled chicken. Then, press the clicker and reward your dog with a treat. Do the clicker-treat action repeatedly. Teaching your dog to pay attention to the clicker is called "charging the clicker." You can switch rewards later on in the training session to something more mundane like kibble, but using special treats keeps your dog's enthusiasm for the clicker high. Before training your dog to play soccer, teach it how to identify a target. Place 1 of your hands in front of your dog’s face with your palm flat and facing the dog. When your dog sniffs your hand, click the clicker and give your dog a treat with your other hand. Repeat this at least 3 times to reinforce the behavior.  Then, begin moving your hand to either side and up and down to train your dog to find the target in a different location. Click and reward your dog each time it sniffs your hand. Clicker training relies on exact timing. Click the moment your dog performs the desired behavior. When you teach your dog to play soccer, the ball will be the target.

Summary:
Purchase a clicker at a pet supply store. Teach your dog to associate the sound of the click with a reward. Train your dog to identify a target.