@Sturgeo 

One of the powerline adapters, the base unit, should be wired to your router. The other unit the remote unit would be the one that is wired to a remote computer.  Since the 9020 has 2 ports on each module you can connect a PC to the frist one but since you are already at the router and if there is an available port on it i would suggest connecting to that for better throughput. .   

@Carl 

Thanks for quick response Carl.  My config is a CenturyLink router (with 4 ethernet ports of which only two are used) hardwired to the base adapter, then to the second adapter where I have one desktop connected to each port.  Wouldn't I see that configuration on one of the desktops, if not both?  I've loaded the TP app and I can see both adapters; it appears that the adapters talking (?) to each other.  Just not visible on Windows?

@Sturgeo 

Yeah that would be normal.  These are generating a network the are esentially cans on a string and wired devices.  If you had a WPA device like the TL-WPA8630 you would see a network available because the w stands for Wireless and has an added WAP to the wired adapter functions. With having just a PA or wired only system they would simiply extend the wired connect of your router and not show up as their own network.

@Carl 

Kinda thought that would be the answer but thanks for the affirmation.