Complex sentence: Mouzo went on to make a record 426 appearances for Boca in all competitions, 396 in the Argentine league, making him the player with the most games in the history of Boca Juniors.
Split into simpler sentences: Mouzo went on to make a record 426 appearances for Boca in all competitions, 396 in the Argentine league. Making him the player with the most games in the history of Boca Juniors.