I have just purchased a pair of BT Mini Connectors (broadband extenders not Wi-Fi extenders) June 2019 to connect up a BT TV Box. Connecting up went well as far as blue lights indicate, so hopefully the BT Box is happy with speed. Let’s address the extenders as one near router as primary and the second one near TV as secondary one. I noticed that on each extender is a second port and decided to add a cable to my Mac mini from the secondary unit, I put a cable into port 2, and checked the speed, I got a 1/10 of what Wi-Fi gets. So then wondered if I need to take a second cable from the router into the second port on the primary extender, on doing that it locked up the Mac mini. I can’t find any documentation to help me add a second device, please advise of correct method.