If the car has a bad battery the battery will not charge just becaus you put a new alternator in try raplacing the old battery.
Repair the alternator to battery connections or replace the battery.
you need a new alternator.
If it the 3.8........start by disconnecting the battery. Then remove the sepertine belt. On the back of the alternator, there is a red cable and a plug. Undo those. Then there is only 3 bolts. Two in the front, one on the back.
Only if the old battery is defective
My advice is to charge the battery with a battery charger before starting the engine. You will be putting a heavy load on the alternator if you allow it to charge a dead battery. This could damage the alternator.
You have a bad alternator.
Not likely, but running the engine with a dead battery can damage some alternators. Always fully charge the battery when installing an alternator.
Normally it means the alternator is defective.
Alternator is not putting out a charge.
An alternator is designed to keep a fully charged battery at peak level. It is not designed to charge a dead battery. Installing a new alternator on a car with a dead battery can in some cases ruin the new alternator. Fully charge the dead battery before starting the engine.
It could be your alternator is going bad
Kills alternator? don't you mean kills battery? Installing a new alternator without first charging the battery well (2amp for 8hrs) will quite likely burn up a new alternator as well as being hard on the battery.