question Zetor 5718 Compressor problem!

Does anybody know how to enable the air compressor of
a Zetor 5718. In the manual it says to lift the little hook on top of the compressor then push the other little hook into the compressor.
I've tried it but I can't get it to work, it just sounds like it's grinding against something inside the compressor.
Very thankful for help

Maybe it is grinding gears when the motor is running.. maybe you should put the motor off first, so that it doesn't rotate..

Actually i dont know how it engages.

Yes you can hear some noise from the wheels, but if it not will go with the engine stopped you can try when you have the engine to run so slowly as possible and you need a little more of power in your fingers. When you try to put in the knob, you do it fast and with some power. In that way it was on my Zetor 6245 and I think its the same for you, not so good music for the ears but the only way I think.
Good luck.
Tage W.