Each of these 'views' has a different set of menu options that correspond to the available actions.
To view the list of all available newsgroups use the 'y' command to "yank-in" all available newsgroups. (To return to the list of groups to which you are subscribed press 'y' again. (*)
Additional menu options are displayed on the screen.
Next unread - the TAB key will allow you to jump past postings which you have already read to the next 'unread' posting. This is especially handy when there have been twenty-three postings on a particular subject/thread and you have already read fourteen. If you have selected this particular thread, the TAB key will take you directly to the next unread posting (in this example #15).
Catch-up - when viewing the list of postings to a list you can use the 'c' or 'C' commands to mark all the articles as read and either return to the previous (group selection) menu or the next unread group ('C'). These commands are handy if there are a number of postings that you don't wish to read now and don't wish to see at a later time.
Toggle all / unread - Messages that you have viewed, or which you have marked as 'read' will not show up the next time you check for postings in this newsgroup. To go back to a message you have already read use the 'r' command to toggle between all messages and (only) unread messages.
Several of the commands available in the message view are also
available in this view... Use the 'h'elp command to review the full list
of commands available.
When viewing an individual posting you can:
Yanking in Newsgroups.
How To Post To A Newsgroup?
Why are some groups not available?