The basic system I have is a TL-PA7017 kit where my router feeds one adapter via an ethernet cable and in another room a second adapter feeds a smart TV via an ethernet cable therefore the assumption is that internet data is available on the house mains circuit. 

What I want to achieve is WiFi in another room that is part of the same house mains circuit. To do that, on the advice of TP-Link Support, I bought a TL-WPA7617 WiFi Range Extender - not part of a kit - with expectation that it would create a WiFi zone. Having followed the install instructions so far achieved is the Power LED lit and similarly the WiFi LED, but no Powerline LED and no internet. It would seem that it's not a simple as pairing with another Powerline device which was the expectation - apparently not plug-and-play.

Advice please on what I need to do to achieve such a simple aim.