It has been a while but:
Those metal pieces that the strap attach to are used as levers. They hook under wings on each end of the top plate and can be used to gently pry the camera straight upward out of the body shell. REMOVE THE LENS FIRST!! When you look at the camera with this in mind, I think that it you will see how it works. Pretty Cool. You got a camera and a puzzle for the same price
I have a Sekonic Marine Meter II that I have never used but I removed the batteries long ago and have no idea what they were.