The the oxygen sensor itself:
Pin 1 is ignition power from the fuse inside the PDC.
Pin 2 should go to a good clean chassis or engine ground. It was G105 in your donor truck.
Pin 3 should splice into the other sensor grounds supplied by PCM, by splicing into S118 of your donor truck.
Pin 4 should go to PCM connector 1, and it looks like it should be pin 24 on a 1999 5.9L donor truck without heavy duty emissions.
Also, if you want left and right bank oxygen sensors instead of one upstream and one downstream, it looks like you would need to have your PCM programmed with heavy duty emissions, and then change the oxygen sensors and wiring to match that layout.