You first select the upper 1/2 or lower 1/2 with...
a: the upper and lower buttons or
b: select the upper/lower sections with the buttons in the right to the screen (Not in Big Font mode)
when the sound/sections that you like to change is in highlight, push Syth, then you see the Staff in the right botton corner and change as you like....
a: with the buttons above the sliders to move the octave or
b: the sliders.

Sorry my English.