How do I set up connections for my two Xbox’s?

Hi, I live in an apartment complex. I have a modem installed connected to a coaxial cable in my living room. It provides WiFi.

I have an Xbox in the living room, and an Xbox in a bedroom. I can route an Ethernet across the living room from the modem to the living room xbox, but I don’t have much of an option for the bedroom one.

I have Ethernet connections in the wall in the living room. I called my ISP and they said to connect the modem to an Ethernet in the wall, and then plug a router into the wall and into my Xbox. But there’s no Ethernet in the wall near my modem in the living room?