You will need to have tie downs installed in the floor, attached to the trailer crossmembers. Any reputable trailer shop should be able to do it for you. Have 4 loop style tie downs placed just outside the track width of the Jeep, and use four straps from the frame to the tie down loops in an x pattern. (ie. left front of frame to right front tie down, right rear of frame to left rear tie down, etc.) And make sure the straps are rated for at least double the weight of the Jeep, a 7,000 or 10,000 lb strap will be plenty. You can also tie down to the axles, but in an enclosed trailer I prefer to limit the suspension movement of the vehicle to keep it away from trailer walls and such, it also makes the trailer handle better as the vehicle suspension cannot bounce.