First you need to remove the recoil pad. It should be held in place by 2 phillips head screws. If the recoil pad is a type like a Limbsaver you will not see the screw heads but will see 2 indentations in the pad, stick your screw driver in the indents and you will "feel" the screw heads.
After you remove the recoil pad you can look down the hole in the stock and will see a flat blade screw way down in the hole, get a long screwdriver and remove that screw.
how do you take the stock off a remington 870 wingmaster 12 gauge? And the buttpad.
Be careful with the stock screw I'v seen a couple stocks that were split cause the screwdriver got between the screw and the side of the stock and
cracked the stock. Get as wide a blade as will go into the hole and don't do your Incredible Hulk impression and it should come right off.