After installing the plugin, head to Reader > Feeds, and click the “Add New” button. On the next screen, enter a site or feed URL.
Feed Reader will then show the feeds it found at that URL.
Click the feed you’d like to subscribe to, and fill out or correct the site name and, optionally, site URL. Pick a category. (By default, there will be just one category, “General,” but it’s really easy to add more.)
Now that your first feed has been added, Feed Reader will regularly check it for updates. (Future items will show up as “Unread,” so you’ll never have to miss another update.)
That’s really all there is to it. If you’ve ever used another feed reader, you’ll find your way around in no time.
Categories
Although categories are optional, they make browsing around a whole lot easier, especially when the sidebar is enabled (on the desktop).
“Uncategorized” feeds will not show up in Feed Reader’s sidebar or OPML exports.
Each feed can have exactly one category. (These categories have nothing to do with WordPress’ post categories, by the way.)
OPML
Categories and feeds can be exported in OPML format, and imported from OPML, too.
Settings
Have a look at the different options under Reader > Settings.
Collapse Menu
Avoid distraction by auto-collapsing WordPress’ side menu while reading. This only affects “Feed Reader” pages, not WordPress’ admin interface as a whole.
Hide Sidebar
Enable if you do not want Feed Reader to show a list of categories and feeds.
System Fonts
By default, Feed Reader presents content using Inter and Merriweather. Enable to use system fonts instead.
Show Actions
Adds a row of “action buttons” below single entries. These let you reply to, favorite, or bookmark feed entries directly from your reader.
If your site supports outgoing webmentions (or pingbacks, and so on), the authors of those entries will receive a notification. (That is, on the condition that their site, too, supports this type of notification.)
Image Proxy
Enable to avoid “mixed context” errors. Will not do anything unless an “image proxy secret” is set as well.
Image Proxy Secret
To prevent abuse, the image proxy requires a (sufficiently random) secret. Use the button to generate one for you. Note: You do not have to write down or otherwise remember this (at all).
Feed Reader Redirect
There’s one more setting, “Feed Reader Redirect,” under Users > Profile, which, when enabled, ensures your reader is the first thing you see after logging in to WordPress. (It only makes sense this is a per-user setting.)