Framestore Question?

I have a live camera in a show that i need to grab a still from and use to freeze the footage onscreen.So i am trying to use the framestore effect but I am having some issues working out how it works. I assume you need the record control on one layer, with the playback effect on another. But i can't work out how to make it all come together to achieve what i want.

Any guidance would be greatly appreciated, i'm sure i am going to kick myself one i understand where i am going wrong!!

Cheers

Gareth