@woozle Thank you. Knowing what to look for, I went in via the Tether app and altered the Security for the 2.4GHz and then my iPhone askd to share the password wih my laptop, and I was linked up....

@woozle Thanks for that really informative reply! The screen shot you included - how do I get to that window, do I need to download a driver onto my mac for that?

tp-link Wi-Fi 6 Range Extender. AX1500, RE505X. I've installed and set up the range extender, and moved the plug and successfully positioned it upstairs near the dead area. All lights are solid blue....