If your looking for how it works, I remember; Use a flat Square or Circle and make Transparent. Apply a Flare made in PhotoShop, PaintShop, whatever and place at a slight angle between your character and the camera. Position a light 'Behind' the camera and to the Left-or-Right. Play with the position of the Square/Circle and Light for the desired effect. Different "Lense Flares" with different colors, etc to gain various effects.