Investigating setup for a relative who has recently moved into a rental. 

The UFB connection is terminated at the neighbours property, not having actually seen the ONT the property manager states its... (her words)

"For the internet, the address is registered as The Actual Address of the main house, not the rented unit . The connection then comes off Port 2 on the ONT located in unit 2.   Chorus don't take note of the unit numbers, so just using the number of the main house and saying that its Port 2 of the ONT will work. "

I have changed the address to the words in bold.

How does this setup actually work? 

Two accounts with one ONT... I'm not sure about any of it.