Question installing Multiple Whonix-Workstation


I am new to Whonix and still new to linux and have been reading many parts of the WIKI about what Whonix is for/can be used.
Whonix is working well as setup by default description, so there is not problem.
I setup Whonix (non qubes), cloned the workstation, started the workstation, closed it and set up a new MAC address as described in the WIKI, started again the workstation.
Now trying to follow the WIKI “Multiple Whonix-Workstation”

Going into the terminal
I do have a problem in opening, changing and saving the file:

3. Edit the network interfaces file in Whonix-Workstation.
Open file /etc/network/interfaces.d/30_non-qubes-whonix in an editor with root rights.”
or alternatively (if I uderstood this correctly)
sudoedit /etc/network/interfaces.d/30_non-qubes-whonix

When typing in:
user@host: sudoedit /etc/network/interfaces.d/30_non-qubes-whonix
I get several error messages like:
(mousepad:2125) dbind-warning**:10:39:23 517 error retrieving accessibility bus address: org.freedesktop.DBuS.error.Service unknown. The service name was not provided by any .service file.
And many more error messages.
The last line reads:
8 The style property GTkWidget:focus-padding is deprecated and should not be used anymore…
But I could open the file at least.
What am I doing wrong?

Also, in the WIKI it is said:
“Change the last octet. For example, change to”

Inside the 30_non-qubes-whonix file, there are 3 lines:

iface eth0 inet static

Does this means that ALL of those 3 should be changed at the end? Or ONLY the gateway?

It would be super nice, if anyone could give me a helping hand with the setup of an extra workstation, like giving me the excat line on what I have to type in.
Please be easy on me! I am learning and just starting with Whonix and english is not my native toung…
Thanks in advance for any help!

OS: Linux Mint 19.3
Whonix: latest
VM: Oracle VM VirtualBox 5

Hello, welcome to Whonix forums and thank you for your question!

This was clarified just now in the wiki.

Look for line address . Change the last octet. For example, change to

Non-issue. There are a lot nonsense messages in Linux distributions unfortunately. See specifically Bug Reports, Software Development and Feature Requests and Bug Reports, Software Development and Feature Requests generally.