I'm going to show you a basic color wheel and how it works, as well as explain color schemes and color dimensions.
The basic color wheel consists of these 12 colors: yellow, yellow-orange, orange, red-orange, red, red-violet, violet, blue-violet, blue, blue-green, green, yellow-green.
It is split into these 3 main groups:
Primary colors: Yellow, red, blue. No other colors can be mixed to make these colors.
Secondary colors: Green, orange, violet. Mixing the primary colors will get you these 3 colors.
Monochromatic: 1 color in a variety of shades.
Complimentary: colors that are opposite each other on the wheel.
Triad: Any 3 colors that make a triangle on the wheel.
Another dimension of color is the saturation of it. Saturation is how pure the hue is. Colors on the wheel are 100% pure, or fully saturated. The less saturated they are, the duller they look.