How to tilt the smartphone holder

[AirKon]

Hello,
How to tilt the smartphone holder?
I tried by forcing a little but not too much, it does not move.
There is a technique?

 

[Devearl Leo]

Don't think so.

 

[BadMadEd]

Don't think so.

User Manual. Page 34: 7. Mobile device support. It is used to fix the mobile device with the adjustable viewing angle.
How? I don't know