I messed this bit up too. It says “pull up”. As the iMac laid flat on the table, I pulled towards the ceiling, bending the pins. It should say “pull towards the top of the machine” or something.

I managed to straighten them out with a tweezer. Looked like a couple of pins were missing at the end, but it looks ok.

Now I have to figure out what I have done to the temperature controller, the fans blow on full speed all the time here. :)