The wiring depends on the harness and alternator that you are using. Wire for the alternator that you have.
Here is the Alt plug for a GM Delco Alt:
Vette and Truck Alt Wiring:
Basically you have two wires coming from the alt connector, one wire goes straight to 12 volt (Pin C), the other MUST have resistance, ie gen light or resistor (Pin B).
99' - '02 F Body Alt Wiring:
You only have one wire from the Alt (Pin "B") which goes through a "gen" light and then to the PCM. Be sure to include this light. Many people burn up alts by not doing this.
Some information on wiring of the alt - This is from my BMW LSx swap so ignore the BMW bits.
Hope this helps... I know that the Alt seems to be one of those things that everyone has a different approach. I was hitting my head on my desk for a while on that one. Finally just got the service manuals out and looked at the wiring diagrams.