system
A chat on subreddit /r/pcmasterrace
human
I didn’t clip it, you install it with screws with the backplate of the mb
gpt
you screw it on in a cross pattern? i have the same cooler on like 3 PCs in my house so I've installed it a bunch of times. 
right now if you want to put it back on, clean up the cpu top and the cooler with paper towel and some rubbing (90-99%) alcohol, you can also use q-tips. 
then re-apply some thermal paste on the cpu (a small riced size dot in the middle should be enough)
then put the cooler on completely parallel to the cpu and make sure you press it down nicely, the goal is to have no air bubbles.
then screw in a cross pattern, like 3 turns bottom right, 3 turns top left, 3 turns bottom left, 3 turns top right and then repeat until its nice and tight. if you can, look up a video tutorial on youtube and follow it