Short answers, pulled from the story.
The Bronze Age describes a phase in material culture development where societies produced bronze by smelting copper and alloying it with tin, arsenic, or other metals. This era follows the Stone Age and precedes the Iron Age within the three-age system used by archaeologists.
West Asia and the Near East were the first regions to enter the Bronze Age beginning with the rise of the Mesopotamian civilization of Sumer in the mid-4th millennium BC. The Maykop culture of the North Caucasus produced the oldest-known bronze as early as the mid-4th millennium BC though they only had arsenical bronze.
In China the earliest bronze artifacts have been found in the Majiayao culture site dating from 3100 to 2700 BC. The production of Erlitou represents the earliest large-scale metallurgy industry in the Central Plains of China.
Around 1200 BC major Late Bronze Age societies experienced sudden systemic failure known as the Bronze Age collapse due to factors like drought famine and disrupted trade networks. The Aegean collapse has been attributed to the exhaustion of the Cypriot forests causing the end of the bronze trade since experiments show charcoal production on the scale necessary for late Bronze Age bronze production would have exhausted them in less than 50 years.
The production of complex tin bronzes lasted for about 500 years in the Balkans before disappearing at the end of the 5th millennium BC. A 2013 report suggests that the earliest tin-alloy bronze was a foil dated to the mid-5th millennium BC from a Vinča culture site in Pločnik Serbia though this dating has been disputed.