Network Manager

I tried to install the Network Manager in the following way: Yast > System > Network Settings > Global Options > Network Setup Method

( Wicked Service | Network Manager | Network Services Disabled )

After selecting "Network Manager" and clicking "ok", the following warning message appeared in a small pop-up window: Applet needed NetworkManager is controlled by desktop applet (KDE plasma widget and nm-applet for GNOME). Be sure it's running and if not, start it manually. How and where can I get the KDE plasma widget mentioned in the previous message and how do I install and start it? How do I program the Network Manager? Thanks in advance for your help? Wolfgang