Ammo10

Hey guys...I need some help quick, fast and in a hurry as turkey season opens tomorrow for me. I just got a new SBE II with ComforTech stock. I'm trying to install a steady grip stock and I'm having no luck. I'm constantly left with about a 1/4 to 1/2 inch gap between the stock and the forend...it will not flush up. I can't find a manual or instruction anywhere on how to install the steady grip. In addition, I have no idea what that little rubber piece is that came with the steady grip. all I can figure is that it goes in the space where the grip meets the forend, but how does it go in? I appreciate any help guys. Thanks.