69 Cowl induction throttle switch install

[Jonesy]

69 Camaro. Everything is original or NOS.

I am trying to figure out how they got this throttle switch and retainer in the hole on the throttle arm.
Fricken broke my first NOS switch trying, now on to the next switch.

Is there some trick I dont know about?

Do you put the retainer on the throttle switch and then put it in the hole?
OR do you put the insert on the hole and try to jam the throttle switch in there.

This is tough I tell ya!!!