Great guide. Like some say it is probably not necessary to remove WiFi antenna, but it makes it easier (mine popped off anyway). One person says no need to slide out the logic board, there is no way the drive would have come out of mine without sliding out the logic board. It's easy so just do it. Unfortunately for me the new drive I was installing is about 1mm wider so won't fit in the correct way, but it fit at an angle.

It is difficult to get the drive back in, but I found if you hold the Mac right side up and slide the drive in that it will slide right in to the holes.

Cheers!