Bohlt X160 Guide D'utilisation page 27

2. Unfold the steerer tube
1) Hold the bike and unfold the steerer
tube upright, ensure that the tube
connects seamlessly with the fork
3) Shake the steerer tube to make sure the
handle is firmly locked
2) Fasten the handle of the steerer tube by
sliding it upwards.
4) If you want to fold the steerer tube, press the
handle lock to unlock it