The 4x4 shifter was very easy - twist off and twist the new one on. The auto shifter was more involved. Remove the 2 screws and it should pull right off. Now the challenge.... I've seen people putting on the aftermarket shifter without removing the square shaft cover. But for mine to work, I had to remove it by (1) removing the center console to get to the bottom of the shaft cover then (2) twisting off the weld joints (not difficult). Because the spherical shift rod now left gaps between the shifter cover square hole, I cut out a small piece of ABS plastic, drilled a round hole, and glued it to the back of the shifter cover - no more gaps.
Test fit your after market shifter and make sure you can engage, disengage, and remove the keys from the ignition before putting everything back together. Mine sometimes would not disengage completely and not allowed the keys to be removed. So this was my fix: (1) put on a small screw at the tip of the OEM shaft to give your aftermarket shifter more surface area to push on (2) put some grease on the top of that screw and that should do the trick.
Sorry for the long explanation but what I thought was going to be a 20 minute job turned out to be a 2 hour job and you could save time by getting some heads up. Good luck.