1) The Key Lighting- This is the main light, it is usually the strongest and has the most influential look on the scene. it is placed at the side of the camera so that the side is well lit and the other side has some shadow.
Fill Lighting- This is the secondary light and is placed on the opposite side of the key lighting. It is used to fill the shadows created by the key. The fill will usually be softer and less bright than the key.
Lighting- The back light is placed behind the subject and lights it from the rear. Rather than projecting direct light, its purpose it to provide definition and subtle highlights around the subjects outline