What exactly is your question?
Faulkner is suggesting that in reading as much and as many different types of literature as possible, you will gain a better understanding of how writing works. Analysis think about how the author put the words together so you can understand how to put words together.
Then write try out putting words together. This is trial and error. If it works great. If the words do not work throw it out and try again.
Faulkner is giving advise to would be writers about how to become a good writer.