Those are nuts on the backplate. Whichever cooler you decide to use, you need to use the backplate that comes with that cooler
You'd use that backplate, put the included standoff washers, put the brackets on top then screw the cooler down. You'll find all the directions in the cooler box. The other double screws you do not use, they are for lga2011 not lga1155
That should fit then, both of those cooler will suit several different (but closely related) sockets that might have slightly different spacings, so there will be options in the brackets, it may be that they are overlapping holes, and if you pick the wrong ones on one side of the cooler the other will not fit.
Thanks you for your awsers ! if I understand well I need to remove the "bad" backplate of my motherboard to replace by the one in the box ? I'm not really sure how to do that, just removing my old ventirad and pull the backplate ?