Tried to add an entry and got the message: Select a valid collection first. I have no clue how to do this.
And I have no clue what you are trying to do…
Where are you trying to add what kind of entry?
Kontact > Kalender > Neuer Termin
Ok.
In the “Create Event” dialog at the top you have to choose a calender (collection) where your new event should be stored.
Normally your default calendar should be selected by default.
But you probably don’t have any calendar active at all.
Make sure there’s at least one that has a ticked checkbox, if you create a new one it is disabled by default. (this also applies to the default calendar created at first start unfortunately…)
Added a calendar: Einstellungen > Kontact einrichten > Kalender > Allgemein > Kalender > Hinzufügen. Now I can add events.