How to disassemble hand throttle lever

[CYB4]

Hi,

My hand throttle lever is not fixed in its notches anymore, it slips up, so I can't increase idle at a cold engine start. I think, the notches are worn and also the springs at the bottom of the rods.

Do you have any recommendations how to disassemble the hand throttle unit and what do do with the slipping hand throttle lever?

Thanks