How to use the Toussaint dual color three segment trimmer line? 1.Press and turn the knob in the direction of arrows so that its arrow is aligned with the metal hole 2.The small hole in the trimmer head must be aligned with the hole on the outside of the trimmer head 3.String the trimmer line through the metal hole until the line mark section is in the center middle of the trimmer head 4.Make the orange parts on either side of grass trimmer head symmetric 5.Press and turn the knob in the direction of arrows to make the trimmer line the length you want