Hello,

First, you can configure 9970 as an access point, below is the instruction:

https://www.tp-link.com/uk/support/download/td-w9970/#video

Or you can change the operation mode to wireless router mode and connect the LAN4/WAN port to the powerline adapter to access internet. 

https://www.tp-link.com/uk/support/faq/543/ 

After that, you can connect your device to the 9970 by wired cable or wireless to get internet. 

May it help and have a nice day. 

Thank you Kevin_Z. I used your option 2 and everhting is working fine. Many thanks for your invaluable help.

Although the setup I have thanks to your help works, the wireless speed is insufficient for streaming video. I think that this is a limitation caused by the house wiring which reduces the speed via the powerline adapters. Is it possible to connect the W9970 to the main router by wifi rather than using the powerline adapaters? In other words, use the W9970 as a repeater (I think that that is the correct term(?

Hi, 

The powerline adapter will limit the speed 9970 can get from it; if possible, you can connect it to the host router directly bypass the powerline adapters.

Meanwhile, you can connect the 9970 to the main router by wireless via enable the WDS function. Instruction as below:

https://www.tp-link.com/en/support/faq/447/

Note: Please notice that the actual network environment will affect the performance of the 9970, including the interference. 

May it help and have a nice day.