It has been a long time since I have owned a encore frame, but take out the screws that hold the grip cap, and you will be able to see the allen head.
Just make sure that if you have a barrel under 16 inches on your frame, you need to take it off before you attach the rifle stock.
FWIW When you use all caps on the web it means you are yelling.
No offense taken. It is just one of the things you learn being on the forums.
I still have a COntender, but my primary specialty handguns are XP-100's and the MOA Maximum pistol (Falling block action).
I can run and XP harder than I can with a Encore and it is a more rigid action with none of the forend issues that can be a problem with break opens.