ESSENTIAL b CPL Wi-Fi 500 +DUO

In general, there is no Wi-Fi on a desktop computer. You can add it by installing a Wi-Fi card or using a USB Wi-Fi adapter. However, powerline adapters will perform better than Wi-Fi, so connect the powerline adapter to the PC with an Ethernet cable.

Desktop PC = no Wi-Fi in most cases.
The connection is therefore made via a network cable. Wi-Fi is useless unless you need to move around with the desktop PC :-)

That said, a quick glance shows that you have two network ports and two network cables delivered with your model,

So you can connect your desktop PC to the second block (the bigger one) directly with a cable; this will connect you to the network and there usually isn't much to do.

If the socket where the block is plugged in is too far from the PC, you'll need to buy a longer network cable (they can be found everywhere).

And the Wi-Fi won't be much use unless you have a mobile phone, tablet, etc.

Oh no, that's not it.

A powerline adapter is used to "set up" a network (a connection) between several computers (or IT devices) WITHOUT having to run cables everywhere and using the building's electrical wiring instead.

Through this network, we can share information (files, audio or video, etc.) BETWEEN the machines.

In short, what was your initial approach?