You might find a visual look at some screen shots might help you see the process of an RSS FEED using Bloglines as an example.
If you follow me as I click on a new site by a friend of mine The Voice Queen, called SimplyVoiceonline.com.
If you notice in this case the RSS subscribe button is in the right hand corner right in the header. So I clicked on it
After I clicked the subscribe button I was taken to a page that allowed me to click on a drop down menu that had several RSS feeders. I choose bloglines. Ray already had a membership so I just put his email and password in the slot. I then clicked on SUBSCRIBE NOW
Notice the explanation Bloglines gives you about the features of the Feeder. It also provides an overview. The shot below gives me the option to customize my feed.