How do I properly adjust the shoulder belt height for the driver's seat?

Before driving, move the shoulder belt height adjuster so the shoulder portion of the belt is centered on your shoulder — away from your face and neck, but not falling off your shoulder. To move it down, press the release button and slide the adjuster to the desired position; to move it up, simply push up on the shoulder belt guide. After adjusting, try to move it down without pressing the release button to confirm it has locked into position. Improper shoulder belt height adjustment could reduce the effectiveness of the safety belt in a crash. (Page 33)