Having access to the raw materials is the hard part, depending on where you are. If the place your or any other tribes migrates around lacks the raw rocks, you’re shit outta luck.

Copper and tin are relatively easy to work, as you can melt the metal into an earthen or sand mold. A furnace that can melt it isn’t too hard to create. From that to a steam engine isn’t that big of a jump, the Greeks figured that out but never thought about making it do labor.

Another hurdle is surviving long enough, as you wouldn’t have access to sanitation or medicine.