The temperature that something is at tells us how warm or cold that something is. But, the temperature scale also tells us
the average kinetic energy of the molecules of the something. The faster that the molecules are moving, the more energy they contain, and thus the higher the temperature of the material. At absolute zero there is no average kinetic energy, all motion stops, nothing moves. The temperature scale is relative scale. For the Kelvin scale the starting point is negative 273.15 Kelvins and there are incremental increases. It is simply a way to illustrate how much average kinetic energy is in a conglomerate of matter