hi @Lolkiwifruit,
1. proceed to select the right OS version from the dropdown list;
2. you will be present with a list of categories. click on the
Utilities section.
3. scroll down until you see the first utility named '
ATKACPI driver and hotkey-related utilities';
4. download that file and extract the contents;
5. uninstall the existing ATK Package, reboot, install the new package, and then reboot;
6. try to turn the backlighting with
fn+f4 key combo.