Look up how to make an ethernet wire. Looks like they used some to hook up phone lines. You may need to get a cheap tone generator from Amazon to track where your wires go in your house. And get some wire connectors to bypass a socket if needed.

SMITON 200pack, UY Wire to Wire Connector K1 https://a.co/d/8fpR4bp

Cable Finder Tone Generator Probe Tracker Wire Network Tester Tracer KIT https://a.co/d/2RSk4Am

VCELINK RJ45 Cat6 Keystone Jacks UL-Listed 10-Pack, Slim Profile Ethernet Wall Jack UTP Punch Down Block PoE in Blue https://a.co/d/3bu5geL

You can’t get sick