Mine has the steel butt plate with one screw on top and one in the back. If you have the model with the rubber recoil pad there will be two screws in the back.
There should be two tiny slits in the rubber which you can barely find. These usually take a small-medium phillips head screwdriver, the screws are hidden under the recoil pad so after you find the slits just stick the screwdriver in until you feel the metal screw, then start turning.