From Gentoo Wiki
USE flags for x11-wm/lumina Lumina desktop environment
||Build and install lumina's desktop-utils|
To install Lumina desktop, run:
emerge --ask x11-wm/lumina
A configuration file is installed in /etc/luminaDesktop.conf. Lumina also has a bunch of own configuration tools.
Lumina provides its own replacement for startx to be started from console.
[[ -f ~/.Xresources ]] && xrdb -merge -I$HOME ~/.Xresources exec start-lumina-desktop