Bronze is an alloy, you need Copper and Tin. Tin deposits are generally along the coast line (small shiny looking boulders) and Copper nodes are usually found in Black Forest. One thing regarding the copper node, they are like icebergs, only about 20% of the copper is on the surface, 80% of it is underneath, if you dig out a huge crater you can get around 100-120 copper ore per deposit. Once you have both Copper ore and Tin ore, smelt them into ingots and then use the forge to combine the ingots into Bronze