How to use it:
1. Download it to a folder in your /home partition, or, if you want to use it system-wide, /usr/share/sounds is the place.
2. Run System Settings, and select Applications and System Notifications.
3. In the dropdown list saying "Event source", select "KDE Workspace".
4. Select "Start session". The default sound will be called KDE-Sys-Log-In-Short.ogg. Press the button next to this name, and select this sound.
5. To test it, press the "Play" button at the left side of the name