Step by step guide for idiots ( idiot, me )

Trying to get things buttoned up on starting engine for first time.. Doing a points to electronic conversion (anothe story)..
Before harness was removed, I had all lights, horn, etc working.. Removed engine bay harness, stripped and painted bay...set engine in.. Installed mini starter (my stock cables are a little short (another story)...
Was trying to follow conversion schematic and wire things up.. Piggy-backed to the ballast resistor, wire to coil and plugged in distributor... SO, I put a test light to the piggyback at ballast with key off, nothing...turned key to "on" and had power at piggyback... Dash lights worked, all seemed good... Battery was low so I put my charger to it...some "sparking" at battery terminal when attaching charger... Gave the key a quick turn to start to see if i had anything...Nothing... then I noticed no dash lights... nothing at ballst piggyback...
What did I f'up now...lol
Not really sure where to start and how to go about it even if i did.. I have a decent multimeter, but haven't much of a clue on how to use it on this situation...
Help..?
OK, look, WE can't imagine what you have

1...What year model is the vehicle?

2...I assume ?? from your comments that this is NOT ? a factory like harness, but a more universal harness? yes? no?

3...What is this "piggy backed to ballast?"

4...Post brand/ model and or a clear photo of your meter, we can step you right through some of that.

5...If your points dist. is in good shape it should not be that hard to "convert back." This would be a better path for engine break in. You want to minimize possible problems when breaking in.

IF THIS IS a factory wiring harness, do you have a diagram/ service manual? If not, you can download many years, free, from MyMopar.com. You may have to accept Dodge vs Plymouth, etc. Also in the wiring section there, are aftermarket/ 3rd party diagrams that are not as well detailed or complete (accessories, etc) but CAN be easier to follow. I often use both