First, you need to enter path to your rss here: http://pipes.yahoo.com/pipes/pipe.info?_id=9207180f4c3eab26a08231eca227b84a
(In example, http://www.pinterest.com/USERNAME/feed.rss)
Then, click "Run Pipe" and "Get as RSS" link
Now you should copy the URL address of opened tab and paste it into Feed URL field of this recipe.
Done.