'86-'13 swap questions

[rodstored-72]

I wasn’t sure where to put this I’ll drop it here. I have a ’86 chevy swb and I have installed a ’13 4.8/4L60E combo. I am trying to figure out the physical wire connections and where to make the connections? My engine is a “drop out” so I have the complete uncut engine harness including a reflashed ECM (lt1swap) and the factory “x2” connector. I have also purchased a factory underhood fuse box as well as the factory power cable that runs from the box to the battery. My ’86 harness is factory and I believe to be original to truck. I have the ’13 engine wiring diagrams and have identified all the wires in the harness and wires to the “X2” connector. I have a pretty good idea (I think) of what wires are what and where they go. I just don’t understand where (between ECM and x2 connector??) to make the connections and how to make the connections (physical). I have read builds on here and other sites as well as on lt1swap. Everything is identified I am just not sure how to and where to connect.
Any assistance would be greatly appreciated, my build is in the squarebody builds section as well.
Thank you in advance