You will want all the electronics from the donor truck (if that's where you're getting it), or the adaptor harness from Mopar if you are using an actual crate.
This guy put a 6.4L Truck Hemi in his 2012 1500 so you may find some useful info here: https://www.ramforumz.com/showthread.php?t=240258
The 3rd gen Hemis are compatible with smallblock (LA) 727 bellhousings, you'd just leave the top bolt out, but I am not sure if the 46RE bellhousing is different at all (I suspect not) or how you'd run the transmission. There us a 3rd gen Hemi swap page on Facebook that has a list of manufacturers who make adapter flywheels, and they may have a tutorial on 2nd gen Rams too (most swaps are 60s-70s Mopars). It would actually probably be easier if you used a 66RFE so you could use a donor PCM to run the engine and trans.
I know 3rd gen Hemis have been swapped into 2nd gen Rams before and that it requires some fab work, but I can't say just how different the mounts are. There may be someone who offers adapter mounts
2013 Ram 1500 Lone Star Quad Cab 4X4. Bright White (PW7), 345ci Hemi V8, 8HP70, 3.21 gears (LSD rear). Mods list
2015 Durango SXT Southwest Heat RWD. White Knuckle (PW7), 220ci Pentastar V6, 845RFE, 3.45 gears (open). Huskyliners, Catch can. Thread