It is rather a precise means for sharpening, strengthening, and ultimately purifying the mental faculties. Initially one concentrates the mind on a particular object, just as to tame a wild animal, one might tie it to a post. There are many possible objects to use for this purpose. One that many people find useful is the sensation of the breath at the tip of the nostrils, but whatever object is employed, the important point is to maintain a close, alert, and continual awareness of it. At first, of course, we can't.
Concentration is difficult.
It goes against the grain of our distraction. But with patience, perseverance, and good humour, it is not impossible. When the mind strays away from the object one gently but firmly brings it back again - again and again and again. Eventually the concentration becomes more or less effortless and the mind bright and firm. If the mind has been sufficiently stabilised by concentration one is able to maintain an equanimous gaze on the present reality and a direct non-conceptual appreciation of the true nature of our existence be.g.ins to grow.