On the Color Wheel, harmonizing colors are adjacent. Contrasting colors are separated by another color. Red and green are contracting colors. Colors that clash are opposite on the wheel - green and magenta for example. The hue is the basic color that distinguishes one color from another - blue from red for example.
Saturation is the purity of hue.
A saturated blue, for example, is composed only of pure blue color. Adding light makes the color more pale, producing a tint . Adding black, by covering the color with a shadow, gives a shade . In the diagram below the center wheel has pure fully saturated color. As you move to the left black is added to produce shades.