Is UM a standalone OS or an add-on for ubuntu?
official derivative of Ubuntu, see https://en.wikipedia.org/wiki/Ubuntu_MATE
It’s a standalone OS and it’s a variant, or flavor, of Ubuntu: the inner mechanics are the same, it uses the same repositories for softwares and so on, but it uses a different desktop environment. Ubuntu MATE uses the MATE desktop while the original Ubuntu uses GNOME 3 (previously Unity). There are other variants like Kubuntu (uses the KDE desktop), Xubuntu (XFCE), Lubuntu (LXDE)… to name a few.
ahh, bummer. I like the look & feel of UM but don’t really want to install a new OS.
I don’t really care for the ubuntu 18.04 version of gnome…
If you already have Ubuntu installed, you can install MATE (or any DE) along GNOME as the repositories are the same. Then, you can remove GNOME if you don’t need it anymore, though it might be a bit complicated if you’re not familiar with this (as basically there isn’t a single command to do it, you’ll have to identify the related packages to uninstall).
I can guide you through this if you’re interested, though there might still be useless packages that I can’t identify. It’s not really a big deal.
Thanks for the offer, but, I poked around and found a youtube video that explains how to install Mate onto Bionic Beaver! Got it up and configured, awesome!!
Thanks!
Installing it is not the hard part (install a package and reconfigure the login manager), I was rather talking about removing GNOME & its softwares. 
ahh, thanks but it’s easy enough to switch DMs at the login prompt.