What is the Correct Club Face Position at Setup? Square or Slightly Open?

I want to confirm that my club face is in the correct position at setup. I think I remember seeing something in one of the videos about this. What I remember is that when you push your hands forward the club face opens slightly. And there is a reason to do this. Is this correct? And can you direct me to the video that illustrates this? And what is the reason to do it? Thanks, Mike