Complex sentence: The ESMA worked as a detention center from the very start of the 1976 dictatorship: on 24 March, the day of the coup d'état, several people kidnapped by the Armed Forces were taken there.
Split into simpler sentences: The ESMA worked as a detention center from the very start of the 1976 dictatorship. On the day of the coup d'état (24 March 1976) several people kidnapped by the Armed Forces were taken there.