Update Readme

Added installing from kde Discover

README.md

@@ -39,6 +39,10 @@ Plasma 5 shell (plasma >= 5.7), Starting with Version 2.0 (plasma > 5.20).
 
 Version 1.03 and below, with plasma > 5.20 may need to install ksysguardd.
 
+### Using Discover
+
+Search for "system monitor plasmoid" in Plasma Addons, Plasma Widgets.
+
 ### From store.kde.org
 
 1. Go to the desktop.