I followed the https://ubuntu.com/tutorials/how-to-install-ubuntu-on-your-raspberry-pi#1-overview.
It worked OK, but I didn’t find a user-id, but guessed the the user-id was ubuntu. I used the “ip address show” command to get the ip address. instead of “arp” and when i checked on my Raspberry PI 3, the “arp” command has to be installed.