What is the easiest way to install a deb package in Kaos?
KaOS is not Debian based, does not use the .deb package format or package manager.
To add packages you miss to your install, see:
demm The problem is that Google music manager is provided just as deb and rpm package and I don't know where is the source
Fabio You can use AUR's PKGBUILD to install it. You find it at https://aur.archlinux.org/packages/google-musicmanager. Download the PKGBUILD file, and run makepkg -si. You might have to compile some dependencies (not sure if all is in the repo, some might have a different name here).
Then still read the Packaging Guide, it tells you were to look for existing PKGBUILDs.
Google music I think it's in KCP