Just installed my first Ubuntu system. It's Lubuntu build 18.10 I read an article that indicated the first thing to do was check for updates by clicking on System Tools / Software Updater. However, Software Updater is not listed. How do I install that (noob here). Steve
I had the same issue after a fresh install of Lubuntu 18.10. In a terminal I ran the following command: sudo apt-get install update-manager
Software Updater and Software & Updates shows under preferences.
Hope it Helps:)
Your other option is to check the package on Muon Package Manager under systems tools. On the search bar type, plasma discover and the following should come up from the search:
plasma-discover-common, plasma-discover-snap-backend, plasma-discover-flatbackend, and plasma-discover
Install what you need and give it a try. In my system the only package not installed is the flatbackend.