Short answers, pulled from the story.
The Federal People's Republic of Yugoslavia was officially proclaimed on the 29th of November 1945 after King Peter II abdicated. This declaration followed a meeting in Jajce where Democratic Federal Yugoslavia was first declared on the 29th of November 1943.
Josip Broz Tito broke relations with Soviet Premier Joseph Stalin over Yugoslav independence and refusal to accept accusations that his party lacked democratic qualities. The Cominform expelled Yugoslavia from the association of Communist parties on the 28th of June 1948 citing nationalist elements within leadership.
Workers self-management system introduced in June 1950 allowed councils elected by workers to manage businesses and share profits. By 1965 most state controls on production pricing and wages ended allowing small businesses to open though no enterprise could employ more than five people.
By 1975 Yugoslavia held 4,000 political prisoners exceeding only Albania and Soviet Union figures. These numbers resulted from purges during events like the Croatian Spring movement when Tito arrested large numbers of protesters.
The federation dissolved along federated republic borders hastened by start of Yugoslav Wars formally breaking up on the 27th of April 1992. Serbia and Montenegro remained within reconstituted Federal Republic of Yugoslavia not recognized internationally as sole successor state to Socialist Federal Republic.