It took me about two hours to put all of my covers on. This included the headrest covers and front/rear console covers as well. I planned on keeping mine on for good, so I took extra time to make sure I got all of the velcro straps tight and the strings snug and hidden. The fit very snugly, which is why they don't shift at all. One extra step I took was to buy some of the Maguire's Leather cleaner/softner and worked 2-3 real good coats into the leather prior to installing the covers. This makes sure the material is moist since it will be covered up for a period of time. If you've got cloth, it's not that big of a deal. It was helpful to have someone assist me in putting the covers on. One person holds the material snug, and the other pulls the velcro strips tight. Also, you have to compress the seats a little to fit the covers over (again, they are snug), so it helps to have an extra set of hands. There are no "hooks". There are wide velcro strips that hide under the seats that allow you to get the covers really tight, and also a few strings that can be used to snug up any slack in the corners.
-Matt