I highlighted the screws, there are springs on them so be careful when removing them.
Then you will want to remove this small screw in the back of the card.
Separate the heatsink from the GPU. It might be tough because of the crappy thermal paste they use. Then unplug the fan.
My old AS5 application (ewww)
On da heatsink
Get a Q-tip and some rubbing alcohol (I used my sisters nail polish remover because I used up the rest of ours
) and get to cleaning!
Put a rice grain size of AS5 on your GPU die
Get a plastic sandwich bag and put your finger in it like this
And even out the AS5 until it looks like this (pro tip, don't your finger off the die until you got it spread evenly. Then drag your finger off the die and it will keep the AS5 from blotching up.
When you reapply the heatsink line it up perfectly before you put it on, because once its touching the die you CAN NOT remove the heatsink from the die. Don't move it around a lot either.
When you got the heatsink in line always keep pressure on the card, then tighten the screws like you would when you tighten the lug nuts on a car wheel: