How do you change an alternator belt on a 91 Ford Festiva?

To change the alternator belt on a 1991 Ford Festiva, first, ensure the engine is off and cool. Loosen the tensioner bolt and adjust the tensioner to release tension on the belt. Remove the old belt by sliding it off the alternator pulley, then install the new belt, ensuring it is properly seated on all pulleys. Finally, adjust the tension and tighten the tensioner bolt before starting the engine to check for proper operation.