Parts needed and compatibility
OP if I were you and you are attempting to tackle this yourself, you need to scare up a service manual for the donor vehicle. I do wish I was better acquainted with all this, but the fact is I don't have time. There is or used to be a harness you could buy online to do so but they were not cheap. Sounds like you are intending to use the computerized transmission? Is this a 2wd trans? I've been told that "if" the vehicle had security system (OEM) options that could be a problem, but others have contested that.
There are or were various Dodge/ Ram / etc forums that had a few service manuals for download.