Not getting power to the ignition.
I’m heading to O’Reillys to get a volt meter.
Get yourself a test light as well.
What you need, and likely can't get (or maybe you can, "North Forty?" or Tractor Supply?) is some alligator clips and make a couple of jumper wires, as well as a clip lead to reach from the battery to the furthest part of the car IE front to rear, with small wire. Does not matter, no16 is fine.
Also if you can (know) post up a link to whatever specific harness is in the car? Like Painless no XXXX?
Some (likely most) aftermarket harnesses fuse various things that were never fused in the original. This means you have to check that, and those fuses can be more difficult to check. You cannot always "see" that they are blown
