Install the KDE screenlocker config tool
apt install kde-config-screenlocker
Launch the utility with
kcmshell5 screenlocker
or search for screen locking in Application Launcher.
Set image under Appearance.

Install the KDE screenlocker config tool
apt install kde-config-screenlocker
Launch the utility with
kcmshell5 screenlocker
or search for screen locking in Application Launcher.
Set image under Appearance.
Where are the trash files stored?
The file location for the trash is in the following directory
~/.local/share/Trash/
Inside there are two folders. info and files.
info – Keeps track of what was deleted and where it was
files – Contains the actual files
Delete the files in the Trash
To delete the files, select the files then press “Shift + Del”
or right click, hold Shift down and select Delete.
https://askubuntu.com/questions/481329/can-i-restart-the-kde-plasma-desktop-without-logging-out
Appears that the issue is due to something happening with kwin.
Resolve the issue by killing plasmashell
killall plasmashell
And relaunch kwin and plasmashell
kstart kwin
kstart plasmashell
You can install the KDE Oxygen sounds by running
sudo apt install oxygen-sounds
You should be able to open up the “Event Notification and Actions” either in settings or by directly searching for it in the Application Launcher and configure the sounds.
The network manager widget package is plasma-nm. Can install it by running the following command from a terminal.
sudo apt install plasma-nm
You should be able to add the Network Manager widget onto the default panel.
Try installing software-properties-kde and get
The following packages have unmet dependencies: software-properties-kde : Depends: python3-software-properties (= 0.96.24.32.11) but 1.8.8 is to be installed E: Unable to correct problems, you have held broken packages.
Try to install python3 from the bionic from bionic-updates
sudo apt install -t bionic-updates python3-software-properties
Install software-properties-kde
sudo apt install software-properties-kde
If it fails try force installing it
sudo dpkg -i --force-overwrite /var/cache/apt/archives/software-properties-kde_0.96.24.32.11_all.deb
Install Kubuntu desktop
sudo apt install kubuntu-desktop
First add the following repo
sudo add-apt-repository ppa:kubuntu-ppa/backports
Make sure you are updated and upgraded
sudo apt-get update && sudo apt-get dist-upgrade
And if needed do a reboot
sudo reboot
Install the KDE desktop
sudo apt install kubuntu-desktop
Log out, select Plasma and log back in.
https://computingforgeeks.com/how-to-install-kde-plasma-desktop-on-linux-mint-19/
Firewalld
sudo firewall-cmd --zone=public --permanent --add-port=1714-1764/tcp sudo firewall-cmd --zone=public --permanent --add-port=1714-1764/udp sudo systemctl restart firewalld.service
UFW firewall
sudo ufw allow 1714:1764/udp sudo ufw allow 1714:1764/tcp sudo ufw reload
More information https://community.kde.org/KDEConnect
To force the fonts DPI do the following.
Open up “System Settings” and under “Font” Select “Force fonts DPI:” Change the defualt number if needed.
Apply settings and restart the computer.
You might need to do this if KDE is displaying the fonts larger than they should be, or if the title bars are overly large.