I have recently done a socket FM2 install in my media machine, the AMD CAM lever system on the stock heatsink is far far better than intel's stock option.
You may have to use a little more force than you may feel is necessary but it's just a case of hooking both ends of the retaining bar thing onto their respective catches and then moving the lever from one position all the way over to the other if that makes any sense?
Don't be afraid to get too heavy handed with it, it's supposed to be on tight.