Ok, your questions seems to be asking to explain the plot development for this particular conflict. If so, here is how it would go:
Exposition: the boys become aware of something in the woods and are frightened.
Risinig Action: the boys go off to find the beast and are even more frightened when the parachute man (the beast) rises up on the wind. They can't see it clearly and assume the beast is large and active. Simon realizes what the beast actually is.
Climax: Simon stumbles into the circle of boys to tell them what he has learned and is mistaken for the beast.
Falling action: Simon is murdered and his body sent out to sea.
Resolution: The boys won't discuss it out loud, but realize what they have done in their frenzy and fear, and all thought of the beast in the woods is gone - they now are fearing the beast in themselves.