Carsten Rieger is under the id @riegercloud also a member of this forum. Perhaps he wants to comment on this himself. He hasn’t been here for quite a while (more than a year), though.
Unfortunately, (not only) this guide is as wrong as it is bloated. Many of the steps in the instructions are unnecessary. It can serve as an example at best, but you shouldn’t just copy it 1:1 if you don’t know exactly what the individual steps do.
That’s what the official manual is for. You should stick to it.
As you can see from this example, a lot of nonsense and fantasy is being spread, often just to pretend that the author knows more than others.
But I can’t change it, I have got my knowledge from the code itself. Anyone who reads the code will find that the preview providers I mentioned above don’t exist.
Although no error message won’t be issued for this reason, it diminishes my trust in the competence of the author who creates this guide and earns his money from it.
→ Here more information about preview providers ←
Much and good luck,
ernolf