Dynamic characters are typically characters that change throughout the story, are full of depth and are well-rounded and full in their characterization and role in the story itself. They tend to have strengths and weaknesses, and make progress and choices throughout the story. The main character, John would definitely fit this category; he goes on a long and arduous journey, conflicted within himself for his supposed transgressions of traditions and rules, but feeling okay because of signs and his internal thirst for knowledge. He sets out a rather naive boy, but determined, and comes back armed with great knowledge--a heavy burden, although an exciting one. We see his thoughts, hear his fears, and see things through his eyes. So, he is very dynamic. Although not an active character in the story itself, consider the dead man that John discovers, and the Gods themselves. The nature of these Gods changes, through John's eyes, throughout the story. At first, they are all-powerful, wonderful beings who are filled with mystery and awe. By the end of the story, he realizes that they are just men. That is a dynamic change to go through, one that John arrives at only through an increased understanding of them. So, consider the gods as a dynamic character choice. The dead man that he finds also seems to have depth--we are curious about him, and he had layers. Although, he doesn't change himself, so he isn't a typical dynamic character. And lastly, consider John's dad, who we get to know in stages throughout the story, as he dispenses advice and wisdom to his son. He is another dynamic character.
Static characters tend to be very flat, and non-changing. They can typically be described in one or two key words, like "bad guy," or "goofy friend," and don't change much throughout the course of the story itself. The Forest People are flat characters--we know them only as that. They don't have faces or individuality, and remain a threat to John and his tribe throughout the entire story. They don't change, and they are the "bad guys". John's fellow tribesmen are also static characters who do not change.
I hope that those thoughts helped a bit; good luck!