How you use a feed depends entirely on which application you want to use to view it.  Applications that display feeds are called 
aggregators, and are normally used to gather feeds of information from a variety of places and display them in one convenient location.
Probably the most popular aggregator in use today is LiveJournal, although most people don't think of it as such.  LiveJournal allows you to specify other users whose entries they want to read ("friends"), then aggregates feeds of entries by those users into one handy "friends page" for you to read conveniently.
As it happens, LiveJournal can also read the feeds that FicWad (and a lot of other people) produce.  If you have a paid LiveJournal account you can add a custom feed to LiveJournal by visiting 
their syndication page.  If you don't have a paid account, you have to wait until someone else has added a particular feed to LiveJournal before you can watch it.
The last 15 stories posted to FicWad can be seen at 
ficwad_recent on LiveJournal.
If you're using FireFox, you can use its 
Live Bookmarks feature to watch a feed in your bookmarks.
If you're using Opera, you can use the "M2 mail client's feed reader":
http://www.opera.com/products/desktop/m2/rss/ to watch the feed.
If you're using Safari in Mac OS X 10.4 or above you can use 
Safari RSS to read feeds.  (We haven't tried this one yet, but it's a Mac, so we're sure it'll be easy.)
If you're using IE... we really do recommend 
Firefox.  Seriously, though, there are a lot of other 
aggregator programs out there.