It is a DE, like regular KDE, GNOME etc. At your OS’s login shell, you should be able to select it once installed. If it is the only desktop environment on that system, it will not even be needed to get selected as the appropriate session gets started when you login.

Arch (and derivative) systems can install it through the AUR, but I do not know any distribution that offers it through their normal distribution channels (packages sources) already.