Slenderman Monster

[xxxxxxxxxxxxxxxx]

Yup, Traggey's right that's not a game model. It would need to have maybe 5000 -10.000 Triangles at most unless you want it to kill your computer as soon as you start the game Probably even less, the Amensia models don't look like they have a very high polycount.
So before you can rig it, you would need to make a lowpoly first. (You could use the highpoly to bake a normalmap though, so you wouldn't lose much detail)

i've tried of for the love of god cant figure it out and if someone else can i would highly appreciate it

Well that depends - in which program did you try to skin it? I can show you how its done in Maya and I think we could figure something out in 3ds Max too, but if its Blender or something else I can't help you :/