How do you change an alternator on a 1989 Toyota pickup?

To change the alternator on a 1989 Toyota pickup, first disconnect the negative battery cable to prevent any electrical shorts. Remove the serpentine belt by loosening the tensioner, then detach the electrical connectors and bolts securing the alternator. Replace it with the new unit, reconnect the electrical components, reattach the serpentine belt, and finally reconnect the battery cable. Make sure to check the belt tension and ensure everything is secure before starting the vehicle.