[CentOS] Non-gnome desktops on CentOS-7

Is there a writeup somewhere detailing how one installs a non-gnome desktop? 
I have installed both KDE and Mate and both fail with the same error.  (EE) no
screens found.

I am a bit bewildered that neither the official KDE from centos nor the
semi-official mate from epel pull in as part of their install the Xserver.  I
am also bothered by the fact that installing a desktop other than gnome 3 does
not in fact provide one that can be started from the command line.

I am not trying anything complicated here.  I just want to install a working
desktop that is not gnome.  Is this possible on CentOS7?


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