Guild of Writers

iirc you can ignore those errors for the first time so you can generate the keys to put in the file.

That's what the tutorial says, yes: "You can safely ignore all startup errors."
I wasn't aware you were at this stage.

So for:

su - dirtsand

should I ignore this error?:

su: Authentication failure

if so, what am I supposed to do after:

nano dirtsand.ini

which seems to be blank?

It seems that it's not copying the file from dirtsand.sample.ini to dirtsand.ini

Uh, "su"? Why that? You should NOT run dirtsand as root. There's no reason to do so, the only gain you have is that every security issue in dirtsand suddenly got much more severe.

the "su - dirtsand" commando is used to switch to the dirtsand user so you don't run it as root. The authentication failure means that the password you type in it is incorrect and the switch fails. No you should not ignore that error.

The errors we told you to ignore earlier were from dirtsand because there wasn't a configuration file yet and therefore cannot run yet as a fully functional dirtsand server. The authentication error means that the command failed.

Oh, right, the "-" means you want a login shell. Is there any reason you don't just "su dataserver"?
Anyway, this is probably not the problem he's having

PeterC, your questions are mostly related to Linux in general. You might have better luck (and more answers) if you asked on the Ubuntu forums, for instance, or on a Linux development forum. We can help you, but we can't teach you Linux by forum!