Creating a separate SSID for a WireGuard instance

Specifically, I found this thread which talks about doing something similar to what I want, but halfway through the thread the OP gets very rude and there stops being useful information.

And then there's this thread that also talks about doing what I want to do, but there are several steps I do not understand.

Maybe this whole thing is too complex for my skill level but I would like to give it a shot.