[Atrium]

I did a search for this topic and couldn't find a thread. I hope this hasn't already been discussed. But, anywho, on to the question.

I'm extremely interested in designing magazine covers and layouts.
I was just wondering if perhaps Graphic Designers are infact the ones who decide on the magazine covers and layouts? Can anyone please help me out. I would greatly appreciate it.

Any tips/help on starting out would also be greatly appreciated. Thank you for your time.