Whilst most of the time the seam will be the main reason for swing, the way you aim the ball is done with your wrist. This is the device that steers the ball. You can keep the wicket tight and straight causing the seam to be at 90 degrees to the horizon. This will give the ball the correct angle to the air. Alternatively you can keep the wicket loose and rolling causing the seam to an... https://faairplay.ac/