Just hold your knife in your hand, with the bottom and the back of your palm and the front within your fingers. Put your middle finger in the round hole and flick outwards. It'll be sorta hard at first, but its preyy easy to figure out.
Sorry if my description didn't make any sense, its sort of hard to explain.
I understand your instructions fine midget, but visualizing the closed folder held in the so called ice pick grip may help some understand, btw i use my ring finger also
Mostly I use my thumb, but now and then I use my ringfinger, for the reversed grip (the handles in front and the blade backwards). Anyway, it doesn't open as fast as using the thumb. And for a really lightning action, I do the drop.