Unlike other RSS readers, Fox RSS is based on the principle of readling list. Regularly during the day, you can make your selection of articles to read later.
Once you have added your first rss feed, you can start your selection of articles to read later by dragging them to the right. Those you are not interested in should go to the left. At any time you can find your selection of articles in the "Reading list" tab.
When you read an article, it will disappear after one week by default. You can extend or shorten this time at any time in the settings (Menu > Settings).