vyos@vyos# set interfaces openvpn vtun0 authentication
password OpenVPN username username OpenVPN password
username and password in the description are reverse.
vyos@vyos# set interfaces openvpn vtun0 remote-port
<0-4294967295> Remote port number to connect to
the port suggestions are a bit high, and the description would fit on the same row if it was 1-65535