Why not look at its datasheet?
But since they are not made anymore you might not find a datasheet.
Philips used to make them.
The two pins across from each other are the same and you can measure their continuity with an ohm-meter. The other pin is the other contact.
I can't remember which is the adjusting screw.
I can't remember which terminal is the adjusting screw.
Maybe it should be the grounded or common terminal so things near the screw don't affect the capacitance much.
I have a circuit with one of those old trimmer capacitors but I couldn't find it.
Suggestion, use proper English not garbled text-speak.
As for the capacitor, see my comments in the attachment.
The moving vanes should be connected to a point which has no RF voltage, that way there will be little/no interaction when touching the screwdriver slot.