It's not too difficult. Slacken all the body bolts, then take all one side off, tilt the body with a jack, fit spacers and new bolts, then repeat on other side. Fit brackets to lower radiator that should be supplied. If you have an early TJ be aware that at up to 13 years old the captive nuts for the body mounts along the side of the body can rust and break away from the box section along the sides of the body causing problems refitting once the bolts are out.