Complex sentence: By 1963, cadets at the (then infamously well-known) Navy Mechanics School (ESMA) started receiving counter-insurgency classes aided by the film "The Battle of Algiers".
Split into simpler sentences: By 1963, cadets at the (then infamously well-known) Navy Mechanics School (ESMA) started receiving counter-insurgency classes. In one of their courses, they were shown the film "The Battle of Algiers".