hmmm... where to start....
First of all, make absolutely certain that the heatsink will not come into contact with any components on the motherboard, like capacitors, dimm slots, etc. Also test fit all the washers to make sure you select the right ones for your motherboard holes. Once you are certain you are ready to install, attach the lugs to the motherboard, and, making sure you orent the heatsink the right way, and thread the bolts through. I prefer to use all of the washers to ensure a snug fit. Tighten each screw in a diagonal pattern, until they bottom out; it is impossible to overtighten them and crush your processor. Once you've done that, you're done!