There is no such thing as "joining" nor as a "group" in UseNet.  It is simply
a bulletin board.

Just post a question or an answer when you have one.

Don't post the same message independently in multiple groups, though.  Read
the FAQ for each forum, and Google for "multi-posting" and "top-posting" to
learn what to avoid.  (Limited "cross-posting" is acceptable - very limited.)