Congrats, you own a fine rifle. You'll like it even more when you shoot it.
Don't go crazy over add on stuff, unless you're gonna use it for HD. If using for HD put a bright white light on it.
Buy ammo and P-mags and learn to shoot your irons.
Then, put an Aimpoint micro on it and call it good.
The two loudest sounds known to man: a gun that goes bang when it is supposed to go click and a gun that goes click when it is supposed to go bang.