WARNING: This page is about a different car, the 2004 Mercury Monterey and 2004 Ford Freestar. However, it is still accessible from the selected car via links, so may be relevant.
Release the J-clips.
Remove all the seat cushion hog rings (two shown) and remove the seat cushion trim cover.
Fig 1: Removing Seat Cushion Hog Rings And Seat Cushion Trim Cover