Complex sentence: The central character and narrator is a young man named David Balfour (Balfour being Stevenson's mother's maiden name), young and naive but resourceful, whose parents have recently died and who is out to make his way in the world.
Split into simpler sentences: The central character and narrator is a young man named David Balfour. Balfour is young and naive but resourceful; his parents have recently died, and he is out to make his way in the world.