How to add posteo.de account on gnome

There's no existing tutorial on how to add posteo.de caldav and cardav account on gnome yet.

Here's the simple configuration:

Go to Settings -> Online Accounts -> Calendar, Contacts and Files. You need to add the calendar and contacts separately.

Say if you have an email john.example@posteo.net

For Calendar:

Server Address: https://posteo.de:8443/calendars
Username: john.example
Password: [your password]

For Contacts:

Server Address: https://posteo.de:8843/addressbooks
Username: john.example
Password: [your password]

Then you are good to go.