Complex sentence: The symbols for the Volume Up/Down and Next/Fast-forward buttons were replaced with small dots, to make it clear that the buttons were also used to move up, down, left, and right within menus.
Split into simpler sentences: The symbols for the Volume Up/Down and Next/Fast-forward buttons were replaced with small dots. This was to make it more obvious that the buttons were also used to move up, down, left, and right within menus.