For changing the backlight brightness you need to go to Options > Screen/Keyboard. I believe the options are there.
For re-arranging icons in the ZEN theme I believe the first 5 icons in the list will show up on the main screen. What you have to do is go to the application list, then move the icons you want to show on the first screen to the first 5 slots. To move an icon, you hold down the ALT key, and then press in the trackwheel while an icon is highlighted. Then you will get a menu where you can manipulate the icon.