This is part of the problem. It is not easy for new users to access...

First, you need access to a news server. These folks offer a free public one: https://www.aioe.org/ There are also other paid news servers but I don't want to advertise for them.

You also need an NNTP (Usenet) client. I use "slrn" which is a command line app. See https://en.wikipedia.org/wiki/List_of_Usenet_newsreaders for some others.

Once you find one, you'll need to point it to the news server of your choice (nntp.aioe.org in this example.)

Good luck discovering Usenet! Most groups are not too active.