THe instructions come with the cooler itself. What you do basically is, pop off the pressure point prongs on the original heatsink. Clean off the thermal paste on the GPU with an Isopropyl solution and a Q-tip.
If the paste isn't already on Silencers heatsink, then add a drop to the GPU. It should come bundled with the Silencer package.
Take the Silencer, align up the mounting holes onto the card and the GPU. Put the screw points on thru the holes and screw it on.
Do NOT over tighten the screws into the card. Should only take 3 turns to tighten it.
Plug in the fan adapter, and make sure no thermal paste has dripped or bled off the sinks edges.
Install the card into the slot and power up the system.