OK, think of an RSS Feed as a stream of an updatable information list.
They aren't for everyone and I find I usually browse RSS Feeds on my mobile devices like the iPhone and iPad.
So when you're waiting for the train to pull into the station, you could browse the latest updates of your chosen GeekandJock Community Groups in a list format so you can quickly keep track of the latest blurb.
Quick With a Click
Once done and depending on your computer and web browser, your associated RSS Feed Reader will open, prompting you to add the new Community Feed to your current ones.
That's about it.