Nothing will happen, for your PC will not be able to receive an IP address from anywhere. You need to configure a static IP address in the same range as the AP's default IP address.

Quite obviously you need to disconnect the PC from the router's network too, such that you can engage a direct connection to the unconfigured WLAN AP. You may need to assign your PC's LAN port a...

One last time: Disconnect the thing from the router's network, and then configure it through a direct LAN connection, such that it integrates into the router's network properly. THEN bring it back...

So? Disconnect the adapter from everything else, reset the powerline connection so it loses connection to the router. Now connect a LAN cable to the PC of your choice, and configure it properly...

Those WLAN access points do have their own configuration software built in. Access is through regular browser software and their (default) IP address.

Ah, so these aren't just powerline adapters, they are WLAN Access Points too. The manuals for these are available online. They both have a full reset capability somehow. From there, their default...