Creating a Recipe for Engadget Distro?

[kichigai]

One of the recipes I've noticed is absent from Calibre is one for Engadget's every-so-often-published online magazine, DISTRO. It's available as apps for Android and iOS tablets, and available as a PDF. What I'd like to do is try and build a recipe that would simply download the latest PDF (if not already done) for transfer to my eReader, like any other recipe.

I can find instructions for pulling information from an RSS feed, or even extracting content from the web page, but pulling down files directly seems to be absent. Any ideas?