Explain the role of iron working and trade in the development of villages into towns and cities?

The Noks made iron tools and used enormous amounts of coal to fuel their iron smelting so with more advanced tools the farmers can clear their land and grow crops efficiently than with stone tools. This quickly traveled across West Africa and it was highly need for farming and such so it was traded for very often. :) THIS IS FROM THE HISTORY ALIVE, THE MEDIEVAL WORLD AND BEYOND BOOK :)