[kubuntu] Kubuntu keyboard not working for ¨e and ^e

I'm using Kubuntu but I can't type the characters ê and ¨e

- in Windows: when I do ^ followed by e I get ê
- in Kubuntu: when I do ^ followed by e I get ^e

Looks like I need to tell my right Alt Gr what to do ("Right Alt is compose") as you can see here:
https://www.stefaanlippens.net/accen...erty-keyboard/

But I don't know where to find these Layout Options. They are not in the Keyboard options.

Any ideas?