I just installed Gnus, started it via ‘M-x gnus’ but it only says "nntp (news) open error", what to do?
You've got to tell Gnus where to fetch the news from. Read the documentation for information on how to do this. As a first start, put those lines in ~/.gnus.el:
(setq gnus-select-method '(nntp "news.yourprovider.net")) (setq user-mail-address "firstname.lastname@example.org") (setq user-full-name "Your Name")