Connect to the Nextcloud Box with SSH? ipv6 error?

My NextCloud box arrived yesterday, and I have put the RaspberryPi 3 image on the microSD card and NextCloud is up and running on my wireless router (I am in the UK, using a BT smart hub). I wish to enable SSH access so that I can make backups from BackInTime (https://github.com/bit-team/backintime), which can use SSH.

I have followed the instructions at https://github.com/nextcloud/nextcloud-snap/wiki/How-to-connect-to-the-Nextcloud-Box-with-SSH, using the First option: Ubuntu SSO account for out-of-box experience. I get as far as the second screenshot under ‘At the beginning of OOBE, the device will prompt “Press enter to configure”’. At this point the following message appears: 'ipv6 is not configured but has mac address[and a mac address is provided].

Could anybody enlighten me regarding what I should do next?

With grateful thanks.

I would suggest trying this option:

But if your network is not properly configured for either IPv4 or IPv6 then you will need to fix that to access your Box.

Thank you . I shied away from trying this because I did not understand it completely. But I could try, if somebody could kindly provide me with a little help.

I do not understand fully what is required: may I ask a few questions (these arise from the four bullet points under ‘Second option: Creating a Core System User’?

  1. On my laptop I run Ubuntu 16.10 rather 16.04. Can I proceed anyway?

  2. What do I need to use for the Brand and Model of the device? The text states ‘The ​ brand ​ and ​ model ​ you use must be correct. They must be exactly what the device provider gave you (including capitalization)’. Does this refer to the NextCloud Box and, if so, what are they?

Finally, the system-user: should this be one of the users that I have created on the NextCloud box (such as my name, which I use to login at nextcloud.local) or is this a completely different matter that requires a separate user?

Further down in the post it says 'You also need a username and password for the account to be created on the device. In this case we use “myuser” and “mypassword”, under the heading ‘Create your system-user file’. Is this something different from the system-user (e.g. a ‘regular’ user on the NextCloud Box)?

With grateful thanks.

With reference to my post above, I have to confess, somewhat shamfacedly, that I have discovered why I could not set up ssh using Option 1. I have now being able to do so.

This leads to a subsequent question: does it make any practical difference whether I use Option 1 (Ubuntu SSO account for out-of-box experience) or Option 2 (Creating a Core System User)?

With thanks