Mounting sled in car?

How exactly do I mount the sled in the car? There doesn't seem to be any holes for me to screw it into a secure place.

You bend the tabs in like in the attached photo.

You can also do what Tony Fabris did and screw mount it. This is not how the sled was designed to fit, but he and others have had success with it. See his pics here.

Ok thanks alot. I would have never thought to bend the tabs. They seem pretty tough to bend. Was it difficult to install this?