I can rejoin this now that I have wimped out on my ride for this morning.
It was cold when I left but didn't think much of it. Until I came out from behind a hill and got in the face by a wind that hadn't been there before.
I looked out over the lake and thought - uh, oh.
I got home some time after the rain started coming down sideways ...........
ANYWAY ......
The cleats in 1 and 3 are the same thing. Just that one of them ( #3) is upside down, and #1 is how you would see it mounted on your shoe.
For some reason the diagram in #3 shows the base plate upside down, those pins should be facing AWAY from the sole of the shoe and the raised "horseshoe" fits onto the pins, then the cleat mounts in the centre of the "horseshoe" - sort of achieves the same thing as the cleats on your MTB shoes in that it recesses the cleat - so you can walk, or put your foot down, without wearing the cleat down.
Bad description, I know - but I'm cold and wet, and miserable.