I went to https://groups.google.com and searched for boot ring seat, looking for a specific Usenet message that I know has those three words in it. No results. All right, I thought, maybe I'm misremembering the Usenet message. So I searched instead for whenever — there must be some Usenet messages with that word in it! But still no results. (It says "Posts: 0, groups: 1354".) (These searches were done when not logged in to Google.)
What am I doing wrong? How do I search for Usenet posts by keywords in them?
Some notes (that you can skip) about the research I already did toward answering this question:
There is a help link on that search-result page, but there's nothing about searching listed there. The most promising subtopic is "Learn how to read and create posts", which doesn't actually answer this question.
I also did a Google Web search on searching Google Groups Usenet, but the top few results were unhelpful. The top one is from 2010, so I skipped it as likely OBE; the next promising one is this SU post, which is about browsing a newsgroup rather than searching by keyword; etc.
Best Answer
In order to search Google Groups, you need simply to be signed in with Google Account otherwise you may encounter no results or various errors like:
Once you are logged in, you are able to search it as usual Google Search pages:
And as regular Google Search, it supports all search operators: