Beginner's cheat sheet on KDE
1 kde overview
2 Navigating Windows
The kde logo (top left for me, but could be elsewhere) allows you to search for an application you want. Just start typing.
2.1 2-finger swipe up/down to switch virtual desktops
This works but seems "jumpy" and "touchy"
2.2 Opening an application
kde logo, then navigate to the application and click.