The + before the method declaration indicates, that this is a class method. So you have no access to instance variables.
You're on the right track, but unless you have many different highscore tables you don't need to make it a separate class, as you've tried to do now. (I.e. 'create many highscore table instances with a class'.) You can of course use a class and create an object of class highscoretable at alloc init (as yan kun shows), but if all you need is a mutable array to add highscores to in your game, just allocate one in the app delegate, or use other methods for variables shared between viewcontrollers, I think.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.