Situation: to use F5 and F6 for decrease and increase of brigthness, respectively, in Asus Zenbook UX303UA, when I can change brightness in System Preferences
Ubuntu's docs says, but it is outdated and does not particularly include 16.04
NOTE: As of BIOS update 214 "Support Windows8 brightness control" is added. This means that the brightness buttons won't work in Ubuntu any longer. Brightness workaround 2 in the Zenbook Prime wiki works fine for changing brightness.
Here some Bash scripts about the setup but their bindings are false for the different system.