Alternator hook up

I just got a new alternator made by Dom but have a problem now that i am trying to install it.  I think this isn’t really a problem as much as I don’t know what to do.

The alternator was made for a Pontiac Grand Am but i have a VW Jetta.   Hooking it up to the battery is fine but im not sure how to hook up the other wire or what it is for.  The wire that goes to my stock alternator has a different clip than the new alternator does.  The place where the wire should clip onto the alternator has 4 little metal prongs where the wire from the car should attach..  One of these must be the one I need to hook my wire in my car up to.  I do not know which one to hook it to.  As well, above each set of metal prongs there are some letters that probably mean something.  They are PL and FS.  Do these letters mean anything?

What should I do ?

Thanks

the other wire is the field wire - this wire needs only a ballast resistor and diode hooked to it from the ignition.  the simplest way to do this, is to get a standard 10A barrel diode, and something along the lines of a 200 ohm ceramic wirewound resistor, hook them up in series and connect one end to the positive side of your coil, and the other end to the field wire of the alternator.  what it does is excite the field windings during start up. once excited, the field wire itself becomes a 12v hot (normally, what was done from the factory is - a ALT light was put in the dash, and they ran a hot from the ignition to the bulb, then the other wire from the bulb went to the field connector on the alternator.  when you turned the key on, that light came on, until you started the car - then it would go out unless your alternator was bad.  since you have a gm alternator, there are usually 3 hookups -- one big one - goes directly to the battery, then a plug on the side with two wires.  one of those wires just goes right to that battery wire on the back of the alternator, the other one is the field wire.  if you know what model alternator it is (like delcotron SI-10 for instance) - i can tell you precisely which wire is for what (they usually have a letter next to the plug for each of the wires on that plug that designates which is which - you can probably figure it out from there)