Two things are critical for a successful CB installation.
First and foremost is the antenna installation. Without that part of the job being done properly, the CB won't stand a chance of working properly or well. That includes getting the mount installed properly (!) and getting the antenna tuned via adjusting its length so it puts out as much power as the CB is capable of.
Pay close attention to the below illustration which shows the most popular and best type of antenna mount. The mount must be assembled exactly as shown, especially where that insulated shoulder washer is concerned. If that shoulder washer isn't in place as shown, the antenna will be shorted to ground and it plain won't work.
Also make sure the mounting bracket that is attached to the Jeep has a good bare metal-to-metal contact since that bracket must be well grounded. And where the antenna mount makes contact with the bottom of the mounting bracket, make sure the powder coating, if present, is ground away from the bracket as shown in the drawing. The antenna mount must make a bare metal to bare metal connection at the point where the red arrows are. Don't grind the powder coating away from the top or inside the hole, just underneath.
And for the CB's power connection, the best/cleanest/most noise-free source of power is either directly from the battery or from the power stud under a small snap-off cover located at the rear of the Power Distribution Center located in front of the battery. Other sources of power like some may tap into at the fuse panel can be electrically noisy and cause your CB to transmit/receive static, whine, etc.
Good luck with it. Make sure to tune the antenna once it's installed. If it tunes properly using an SWR meter, that's a clear sign it and its mount was installed properly.