How do you change the alternator on Vauxhall Astra 1.6?

To change the alternator on a Vauxhall Astra 1.6, first disconnect the battery to ensure safety. Remove the drive belt by loosening the tensioner, then detach the electrical connections from the alternator. Unscrew the mounting bolts to take out the old alternator, and install the new one by reversing the steps, ensuring all connections are secure and the belt is properly tensioned before reconnecting the battery.