1. Right-click on desktop and Unlock Widgets.
2. Right-click and choose Desktop Settings > Desktop Activity - Type: Folder View > OK.
(if you get Folder View Settings, you don't have to change the above (2.) setting)
3. Drag-drop item from menu (any menu style) to your desktop.
4. Drag items on your desktop to the wanted position.
5. Right-click on desktop and Lock Widgets.
......... how can I create a non-KDE application on the desktop?
Right-click on desktop > Create New > Link to ....