Value is lightness or darkness of a colour , whereas, saturation refers to strenth of the colour.

Saturation- It defines brilliance & intensity of a color and this intensity of a color changes with the change in amount of grey in any color.

Value- It decides how dark V/s white a color is, which means that in this case we add black or white in any color.

BY ADDING GREY WE CAN DECREASE THE SATURATION AND INCREASE THE INTENSITY AND BY ADDING BLACK WE CAN INCREASE OR DECREASE THE VALUE