Firstly lock the turntable tone arm, unscrew the cartridge, gently remove the stylus from the cartridge body and insert a new stylus. A stylus is changed usually by pulling straight out and in the opposite direction of the turntable's arm. If the stylus doesn't come with direction, try these: with one hand, hold the cartridge to steady it. With the other hand grasp the stylus from both sides and pull. Install the new stylus. Holding the stylus from the top, press it gently into the space at the tip of the cartridge where the old stylus had been. Don't force it.