Drive your tractor along at walking pace and steer to the left or right until the axles of the semi-trailer move into the straight-ahead position.
Check whether the markings on the steering arm or on the axle assembly are aligned in relation to each other.
When the axles of the trailer are perfectly straight you can stop and open the 4 valves in the control box.
Now drive the tractor straight in front of the trailer, the axles of the semi-trailer will stay in the straight-ahead position.
When the tractor is straight in front of the semi-trailer you can put the 4 valves in the control box back into the drive position.
The combination is now aligned with each other.
1: position valves closed (driving position)
2: position valves open (aligning)