Costway SP37672 Manuel D'utilisation page 9

3)Pull out the adjustable knob to adjust the saddle support up to a suitable
height, loosen the adjustable knob and pass the knob through the small hole
of the saddle support, and then lock the adjustable knob.
(Loosen the locking bolt to move the saddle back and forth, and after
adjusting to a comfortable position, tighten the bolt.)
08