Complex sentence: Hersey began by making himself familiar with the work of writers already in the market who were capable of producing the kind of material Ralston wanted, and soon concluded that the new magazine would have to include some reprinted stories alongside the original material.
Split into simpler sentences: Hersey began by making himself familiar with the work of writers already in the market who were capable of producing the kind of material Ralston wanted. He soon concluded that the new magazine would have to include some reprinted stories alongside the original material.