How does non renewable powerstation work?

A boiler, such as a petrol burner or a nuclear reactor, generates heat. This heat is used to turn water into steam which turns turbines. The turbines are attached to a coil that spins around a metal bar, or a metal bar that spins within a coil (this is called a generator). The water carries on going until it reaches the cooling towers, where it condenses and goes back to the boiler. And that's more or less it, in a nutshell.