Hello! You asked about Nick's strategy of reintegration into society as demonstrated by his actions.
In 'Big Two Hearted River,' Nick is a soldier who has returned from war. He has been wounded and has come back home to recover his sanity and his humanity. As he gets off the train, he sees the town of Seney. All that is left of it is the stone foundation of the Mansion House hotel. His symbolic walk away from the town signals that he is ready to leave the horrors of war behind. He is on the way to camp by the Two-Hearted River. Before he goes, he watches the trout in a stream, swimming with the flow of the water. A kingfisher appears and dives into the water for its trout meal. The water and the trout symbolize Nick's need to rely on nature to heal his psychosis, his war nightmare. Both water and fish are also Christian symbols of baptism; Nick desperately needs this solitary excursion into the heart of nature to renew his spirit.
He notices that the grasshoppers he leaves behind are all black, another reminder that even though the dark memories of war follow him, they can never stop him from 'making camp' or seeking healing away from the devastation. The therapeutic effect of setting up camp and the methodical aspects of making his mark on the land provides Nick much happiness:
Now it was done. It had been a hard trip. He was very tired. That was done. He had made his camp. He was settled. Nothing could touch him. It was a good place to camp. He was there, in the good place. He was in his home where he had made it.
Nick eats his simple meal of spaghetti and pork and beans with gratefulness. His slow savoring of his food and his coffee is both a healing and a nourishing experience. His senses are heightened and he is grateful: his journey to healing has started.
Nick gets ready for fishing. He catches grasshoppers as bait and notices that the grasshoppers are not black in this area. Slowly, he again methodically prepares for his fishing expedition. We sense that Nick's scrupulous attention to detail is a calming exercise. He cooks himself some flapjacks and makes onion sandwiches to take with him. Hemingway describes every fisherman's ritual in catching and releasing fish that are too small. He describes how careful Nick is to touch the trout only after wetting his hands.
If a trout was touched with a dry hand, a white fungus attacked the unprotected spot.
Nick's next trout excites him: it is heavy and powerful. Nick is thrilled with his catch, but it escapes. In the end, he manages to catch two trout which he cleans and dresses so that he can take them back to camp for cooking.
He sits down to take in everything he has just experienced. He does not want 'to rush his sensations any.' Nick's healing will come in good time. He will not rush his emotions: the swamp is a deep place towards the end of the river and the rushing waters can be dangerous. Although he knows that's where all the big trout are, he is not quite ready to face the swamp. He wishes for something to read, an indication that he may be ready for deeper analysis and cogitation. For now, he knows that there are 'plenty of days coming when he could fish the swamp.' We are sure that with his careful approach to his spiritual and physical needs, his reintegration into society will come at the right moment.
Thanks for the question.