Can someone explain to me the relationship between the countries of Montenegro, Yugoslavia, Serbia, Kosovo, and the Federal Republic of Yugoslavia

After the end of World War I, in the Balkans, the Kingdom of Yugoslavia was formed by Slovenia, Croatia, the former Austro-Hungarian region of Bosnia and Herzegovina, the Kingdom of Montenegro, and Serbia together, note that it was a monarchy. After the outbreak of World War II, the Kingdom of Yugoslavia was defeated, and Croatia became independent again, establishing the Independent State of Croatia.After the end of World War II, the territory of the former Yugoslavia was basically restored, but the regime was already in the hands of the Tito-led South ****.Although it is a federal state, and although it has made certain achievements in nation building, the economic level between the **** and the state differs quite a lot, with different degrees of development, coupled with a number of intricate ethnic relations, in 1991 Croatia and Slovenia were the first to become independent, then Bosnia and Herzegovina and Macedonia also became independent (Macedonia was part of Serbia before the formation of Yugoslavia, but with a different ethnicity), because of the ethnic problems in the independence of Bosnia and Herzegovina, the war in Bosnia and Herzegovina erupted (an absolute tragedy), and the rest of Serbia and Montenegro (known as Negro in the early years of the Gate) formed a state called the The remaining Serbia and Montenegro (earlier known as Montenegro) formed a state called "Yugoslavia", but in 2003, Montenegro also declared independence, and the FRY broke up peacefully. As for Kosovo, originally an autonomous province of Serbia, mainly Albanian majority, because of ethnic and faith issues, there have been disputes, and then the FRY did not effectively control the situation on the ground, so much so that the current situation in Kosovo continued to be turbulent, NATO began to intervene, (I personally believe that the intervention is necessary), and after the end of the Kosovo War in 1999, the actual Kosovo out of the effective control of Serbia , but not many in the world now recognize Kosovo as a sovereign state.