Make shure you always find a good clean ground location(free of rust & paint). Star washers work great for ground conections because they dig into the metal for a good conection. Then spray paint or grease the ground conection so it won't coroad. Use shrink tube type crimp conectors or soulder all conections to minumize corosion. Just read directions very carefully & take your time because there is nothing worse than hooking everything up & it's not working so then you need to go through the hole thing again. I take it you have an e-locker. Make shure you seal the wire correctly so you don't get a leak in the diff. Could be either a gear oil leak or water could get in the diff. Don't want that!!
Finding a good positive power source would be best directly off the battery but make shure all things are turned off when you let the jeep sit so the battery is not drained. I like to find a Key On Power source so then I no that when I turn the key off that all systems are off as well. Just make shure that the Keyed Power source can handle the load or you will blow a fues. A good Keyed power source is the accory power port or cigerett lighter. NEVER tap into the Air Bag wires or even mess with them. They are usually yellow wires & most of the time are in a yellow plastic conduit.
Electral can be very intimidating at times but usually straight foward. Just get your self a good test light. I have been doing this stuff for years & still to this day am challenged almost once a weak. Sometimes I can spend hrs on an electral issues but then im usually dealing with miltiplex controll units witch are very complex. Now you no why im bald