I just put one in mine. I can talk you thru it, but if you have never done it before it will seem a bit lengthy and involved.
A Wilson/Firestik is a good choice. I fabricated a heavy aluminum mount that bolts to the stock spare tire carrier and terminates a few inches below the top. Onto the mount went the antenna stud, then spring, then 2 ft Wilson antenna, with most of the coil above the Jeep. The CB is on my rollbar with hose clamps.
Plenty of aftermarket hardware is available for this, I just like to do it mydamnself.
Tuning the antenna, soldering the connectors, etc, could take some time if you have not done it before.