How do you wire the alternator to a battery?

It depends on the alternator.
The larger B+ goes to the battery (or starter)
The other wire goes to a globe then to the ignition switch (+). Early alternators the globe was a vital part of the circuit. Later ones it is just an indicator. Alternators with more connections have external regulators, track down a proper diagram.
BE aware : Some alternators will blow up if the B+ is disconnected whilst the engine is running