The best answer I can give you is to show you how to find this in the service manual.
I don't have a '68 Chrysler manual anymore, but I do have a similar digital copy of a '68 Plymouth that will be close enough. Here's a screen shot of the page we need to look at with some highlights.
View attachment 439990
First thing is the bulkhead disconnect. Note the set of 3 "cavities" with marking of ABC etc.
Now see the marked plugs, also ABC etc. highlighted in yellow. Those plug into those cavities. A-E goes into A-E and J-N goes into J-N and so on. Look at the shapes and you'll see the little "bumps" around the outside of the plugs. That keeps you from plugging them into the wrong cavity.
Now for the real mystery of the wiring diagram.... and guys that have been doing this for years don't understand, so you are learning this early. See I've highlighted one wire "J2-16DBL*" . Those all mean something. The easiest and most important is the "DBL" and that's the color. Dark blue and if you're not sure, it's in the bottom right. Also very important is that "*". That asterisk means it has a white tracer which is electrical wire speak for a white stripe on the wire.
Next most important is the "16". That is the wire gauge or size. In this case it's a #16 wire.
The "J2" is the circuit number. Follow that wire down to where it plugs into the regulator and you'll see "J2-16DBL*" repeated again. If this was a long run that went to another page, that's how you would follow the run.
I always like digital copies because I will print out these pages and take my colored highlighters and draw all over them to figure out what I'm doing. If you have a paper copy, my suggestion is have some paper copies made and do the same. It saves a lot of frustration.
Next post, I'll show you how to disconnect the plugs.
