The Remnants of the Alien Dust

After the World War, the survivors discovered that the technology left before the war gradually failed for unknown reasons. Some people accidentally discovered that they could draw strength from nuclear radiation, and this drawing process seemed to be very similar to the descriptions in pre-war cultivation novels. So these survivors started their own cultivation one after another, but in this world where there are no ancient secret treasures, no cultivation sects, and even basic cultivation techniques do not exist, and they only rely on cultivation novels written by pre-war writers and an old man who wants to take away himself, but does not know everything like in the novel, how can he survive, practice, or even create a cultivation civilization from scratch?