Getting it back together is where I struggled.
But using some duct tape, it helped to hold the spring in place
while you fiddle around trying to hook it back up. I used a pic tool and a screwdriver to get it in place. Once the pic is in the hole where the red arrow is, close the mirror tight, pull the pic and the hook will fall into place.
The offset screwdriver is the best tool to remove the mirror screws.
If you wrap the handle with tape, it will not scratch the housing while
making those half turns to get those little suckers out and back in.