Since the PlayBook has no integrated e-mail app, it instead provides shortcuts to the Web-browser services for Gmail, Hotmail, Yahoo Mail, and AOL Mail. But not all is golden: AOL Mail had a graphical blooper (the garbled text shown here) when attaching a file, and since the Gmail offered on the tablet is the mobile version of the service, you can't attach files in it.
Also visible here is the swipe-down menu for the Web browser. See the Downloads icon? This is the primary way to access downloads on the device (the Pictures app and the Videos app each have a downloads folder, too).