I asked a friend for some references. We both work in the field of Aegean Bronze Age archaeology, so that's where these are from, although obviously there are plenty of examples from other places.

At a site called Chrysokamino in eastern Crete, a metallurgical workshop dating to the Early and Middle Bronze Age has been found. Smelting of copper seems to have taken place by using furnaces with chimneys, with a "pot bellows" used to provide a draft. Temperatures of 1200°C were possible with this.^1

In terms of shaping copper and bronze objects, simple shapes could be produced by hammering an ingot into shape , or using a simple open mould to produce a basic shape which could be finished by hammering. Somewhat later, more complex shapes could be produced through using two-piece moulds.^2

In the UK, a man called Neil Burridge works to replicate bronze age metalworking. Here's a clip from a recent BBC documentary in which he casts a bronze sword: https://youtu.be/eEWIuyeNp2k

^1 Betancourt, P. (2006) The Chrysokamino Metallurgy Workshop and Its Territory.

^2 Dickinson, O. (1994) The Aegean Bronze Age, p. 98.