Brightness control not working

jamZ
The installation is pretty simple. Go to the project site on Github and open the Wiki page. Follow the instructions:
https://github.com/KibuKuhn/brightness/wiki/How-to-build-and-install-brightness-on-your-Solus
In short:
This is a java application.
You must install openjdk-11
You must install apache-maven
That's all in the repo.
and so on

If you don't understand the Wiki please post it here