Short answers, pulled from the story.
Albert Kalonji declared the region of southeastern Kasai to be the new Mining State of South Kasai on the 9th of August 1960. He made this declaration while still located in neighboring Katanga province.
The capital of South Kasai was established at Bakwanga with an estimated population of 2 million by 1962. This city later became known as Mbuji-Mayi after being renamed following the state's dissolution.
The South Kasaian army grew from just 250 members at inception to nearly 3,000 by 1961. Floribert Dinanga led this force as a 22-year-old General assisted by nine European officers.
Internal disintegration began when ten of South Kasai's thirteen representatives in the Leopoldville Parliament publicly condemned Albert Kalonji after he declared himself Mulopwe on the 16th of July 1961. These parliamentarians began disavowing Kalonji which marked the start of the secessionist state's internal collapse.
Military commanders led by Albert Kankolongo launched a coup d'état in Bakwanga against the Kalonjist regime on the 30th of September 1962. Central government troops arrived again in Bakwanga on the 5th of October 1962 to suppress remaining loyalists and mark the official end of the secession.