problems with Model EX6110, AC1200 extender

I bought a AC1200 wifi extender model EX6110 about 18 months ago to get wifi to my Ring door bell. it worked for  when we had a Virgin Media rounter. Since moving to Sky I cant get it to work.

Looking at the message streams I have seen similar problems around error messages - can't access any of the websites Netgear suggests.  What is most disconcerting is that the model on the official netgear you tube video doesn't even look like mine.

I just want to extend my wifi signal from the middle to the back of a relatively long, slim house.

I can't het any divice to log into the _2GEXT or 5GEXT authentication problem. I am using windows 10. 

I don't want to do a short course in digital comms, I just need an idiot's guide to how to make it work.  In the old days the people who made it would do this, but now I have to turn to the community for help.  How do I get all four lights to go green?

Thanks.