You may not want to read every article in news.announce.newusers, and it's true that not all of them are necessary. Please do read the articles entitled ``Answers to Frequently Asked Questions'' and ``A Primer on How to Work With the Usenet Community.'' You can get a lot of information about the news reader you decide to use by typing man rn or man xrn.
You might also want to check out news.newusers.questions; in particular, the posting entitled ``Welcome to news.newusers.questions!'' is extremely valuable for new Usenet users.
Finally, the Athena on-line help contains more detailed information about using NetNews. To access it, run help and see the ``Network News'' menu underneath the ``Communicating with Other Users'' top-level menu.