When putting in the backplate, the flimsy metal fingers around each port go where? Do they have a purpose (like grounding)? Should they be flat against the plate or protruding at 90 degrees to the plate? Some times hard to get the board to slide thru the openings.

doesnt really matter as long as they are not blocking any of the ports.

Your guess is correct. They are grounding contacts and are supposed to touch the metal housing on each port. They don't tend to make much difference in some cases, but at other times you can get buzzing noises on your audio if the grounding is poor. Try and make sure they make contact with the relevent ports if you can. They also stop your I/O plate from rattling. You shouldn't need to touch them normaly as they will already be in position.

Guys, forgive my lack of knowledge in this case, and a little off the topic, but what are you talking about?

The metal shield on the PC case, through which all the mainboard mounted I/O ports are exposed.