Three Point Lighting

Name of Light - Key Light
Light Function - The Key Light brings the most light it is the primary light in the three point lighting.
Position of Light - Camera Left, Shooting down at usually a 45 degree angel.

Name of Light - Back Light
Light Function - Ther Back Light cuts the person on the screen out of the background, withut it, it looks like the person is part of the backgroud.
Position of Light - At the back of the set at the top, shining down at usually a 45 degree angel.

Name of Light - The Fill Light
Light Function - The Fill Light fills in all the details without it parts of the persons face are in shadow.
Position of Light - Camera Right, usually shining down at a 45 degree angel.