What you are describing is a very common misconception about the way openHAB handles things and items.
Please read about this here:
In short: PaperUI and configuration files are two ways to manage your things+items. You can combine both (hue lamps in PaperUI, miele devices in file) but the openHAB system will never touch your configuration files. These are under your total control. You are in fact able to use the configuration files only and abandon the PaperUI completely. See:
In my personal humble opinion the better choice.
The documentation under https://openhabdoc.readthedocs.io/de/latest/Beispiel is indeed quite nice! We are actually trying to improve the english documentation as it will be able to reach way more users… If you want to improve the linked german document I believe here’s the project you can open an issue with your ideas.
