I’d be cautious following simple commands and configs without explanation or knowing what they do. And when someone copies public keys via clipboard I’m skeptic. Use ssh-copy-id or at least scp. And with Hetzner you can add your public key to their panel and it will be automatically added to every installation.

As it is stated, this is just a journal / checklist for someone and made publicly available. Don’t blindly follow such things without understanding what you are doing.