Battery light

So I need to replace the alternator and what about the radiator, is it OK?? Do I add antifreeze??

You have an antifreeze leak somewhere. Either radiator or a pin hole in a hose. Pressure test to find leak

You might be able to add antifreeze and start it up and see the leak? Watch your eyes doing this. Add the same color and compatibility antifreeze. This is important not to have it react with aluminum and ruin your water pump if this is not already the issue?