@patrick20, Welcome to the forum. Hope you will be going to enjoy Grav!
There are a few issues with the setup.
You are not using the default English language, but German. Therefor you will have to define the supported languages in ‘/user/config/system.yaml’
languages:
supported: [de] # Add others if needed
Blueprints do not use the language (‘de’) as extension. All language use the same page blueprint. Only the content of the blueprint is translated.
fields:
gallery:
type: tab
title: THEME_KLAR.GALLERY // this will be translated
With the following in ‘/user/config/themes/klar/languages.yaml’:
en:
THEME_KLAR:
GALLERY: Gallery
de:
THEME_KLAR:
GALLERY: Galerie
You will probably want to extend the default configuration in your page blueprint for ‘about-us-me.yaml’. You should therefor tell Grav that it extends the default page: