Hello. I installed new firmware on a Chromebook using https://mrchromebox.tech

I installed Linux Mint Xfce on this machine. I know about the xrandr -q | grep " connected" and xrandr --output LVDS1 --brightness 0.5 commands, which will change the brightness of a display to a certain level (between 0-1). But how would I use the built-in brightness keys on a Chromebook to increase/decrease the brightness? So far, I haven't found any form of the xrandr command that would increase/decrease the brightness by 10 or so percent. If I found those commands, I would still need to figure out how to map them to the brightness keys. Forgive me: I am relatively a beginner in Linux. Any help would be great. Thanks!