I have followed this link https://ubuntu-mate.community/t/cm-storm-keyboard-and-mouse-solved/9816 .
I used this command
sudo xmodmap -e 'add mod3 = Scroll_Lock'
but it's showing me following msg
xmodmap: unable to open display 'desktop:0'.
when I use
xset led 3. it's not turning on backlit.
Can anyone tell me what's going on ?