KAlarm can do both and more (f.e. run a command, send an EMail).
btw - is kalarm a plasmoid - thing - in other words can i find it a t the miniprogrammes
No, it’s a normal application that runs in the background and creates an icon in the system tray.
You can find it in the start menu (Utilities->Time), but I’m not sure if it’s installed by default. It’s in the package “kalarm” and available in the standard OSS repo though.
Just tried that Plasma Alarm Clock. Very easy to use, did work, but doesn’t play mp3. The filter in search dialogue is called “sound”. I suppose it is looking for .wav?
kalarm is definitely more powerful.