How to build an RSS Reader?

Hello there, I need a help. I want to build an RSS reader (or shall I call as RSS feed engine) to learn how it works. This purely for educational purposes. I tried looking around the web and honestly could not found much material on the topic. In a nutshell, think of that I want to build something like feedly or Google Reader. I do not get resources on how to build one. The closest I could get it - http://rss.softwaregarden.com/aboutrss.html - https://en.wikipedia.org/wiki/RSS - https://en.wikipedia.org/wiki/Web_syndication - http://www.whatisrss.com/ Could someone please guide me in this effort?