Complex sentence: Wiranto's involvement with the events of May 1998 began on the 12th, when he authorized Commander of KODAM Jaya Syafrie Syamsuddin and Chief of Jakarta Regional Police Hamami Nata to take care of the situation in Jakarta.
Split into simpler sentences: Wiranto's involvement with the events of May 1998 began on the 12th. That day, he authorized Commander of KODAM Jaya Syafrie Syamsuddin and Chief of Jakarta Regional Police Hamami Nata to take care of the situation in Jakarta.