I think you should take your situation separately.
Connecting UBOSbox to Ethernet is a different issue with UBOS staff.
1. UBOSbox should be connected to the public internet natively when you plug your UTP cable into the box directly.
If not, you should check the physical environment outside the box first.(i.e. cable, ports, internet connection, modem, firewall, VPN etc).
2. UBOS staff plays a roll for the wireless connection. On top of that it also supports the automatic site set up by default.
So you should be able to do that by the default when you plug your staff into the box.
Unfortunately if you can't get any access to the internet, then the box will refuse to install, for it requires connection to the internet in order to download the packages from it.
FYI, any of USB stick can be a staff though. In my case I am using two staffs(one from the Indiecomputing, and the other from my own)
As my advice you should resolve the first thing first(internet connection via Ethernet).