How do you change the alternator belt on a 2003 lancer?

To change the alternator belt on a 2003 Mitsubishi Lancer, first, disconnect the negative battery terminal to ensure safety. Then, loosen the tensioner pulley by turning the adjusting bolt and remove the old belt from the alternator. Install the new belt by routing it over the alternator and other pulleys according to the belt routing diagram, then adjust the tensioner to apply proper tension to the belt. Finally, reconnect the battery terminal, start the engine, and check for proper operation.