To install Lumina desktop, run:
pacman -S lumina lumina-extra
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.
Make sure to read this article, for more information on managing startx on Arch GNU/Linux (the information applies to Hyperbola, as well). But relevant commands are bellow:
[[ -f ~/.Xresources ]] && xrdb -merge -I$HOME ~/.Xresources exec start-lumina-desktop