To Add RSS Streams follow below Steps.
Step 1: Click on NewsStream menu in left menubar. then click on Add New RSSStream
Step 2: Fill all the information on Form, Explanation of all Options provided on below screenshot
Step 3: Once Selected, hit Save RSS Stream, the saved stream will be listed on NewsStream Page with list of sources which you have used.
Also if you click on Posts, you will be able to check the newly added posts.