How does John Boyne use Bruno's naivity and innocence to portray Bruno's life at out with?

Bruno's character is completely innocent. Even amidst the horrors of Auschwitz, Bruno is unaware of what happens around him. He tries to occupy himself, spends hours at the window, and for the most part, he follows the intructions he has been given by his parents. It's only boredom and a desire to explore that lead Bruno to the fence, and even then, he only searches for someone to play with. He doesn't understand why the fence is there, and he isn't old enough to figure it all out.