The first part of the plot is the exposition, which is also known as the introduction. It serves as the foundation for the story, introducing the characters and the setting. In an exposition, the two most important characters -- the protagonist and the antagonist -- are usually introduced. The main character is the protagonist; he is central to the story and connected to its events. The antagonist is in opposition to the protagonist, and is the one the protagonist comes into conflict with. While antagonist is often is a person, it can also be an idea or an institution.
The setting includes the geographic place, the time (such the day and year) and the weather. The social conditions are also important; this includes the characters' daily lives and their environment. The mood is also important to the setting, and sets the tone for the story.
The exposition also includes an initial event, or thought, that engages the reader and sets the story in motion.
The rising action is the second part of the plot. It consists of the events that reveal the conflict between the protagonist and the antagonist. The conflict usually continues through a series of obstacles that the protagonist is challenged to overcome. For example, in "Harry Potter and the Sorcerer's Stone," Harry and his friends must overcome a series of challenges in order to reach the chamber where the stone is hidden. Their struggle against these obstacles is the rising action.
The climax is where the conflict between the protagonist and the antagonist comes to a head, usually as the last obstacle presented to the protagonist. The outcome of the conflict won't be revealed. To follow the previous example, Harry's battle with Professor Quirrell/Lord Voldemort in the stone's chamber is the climax of the story.
After the climax comes the falling action, where the events start to become resolved, and the outcome of the conflict is revealed. To continue following the previous example, the falling action in "Harry Potter and the Sorcerer's Stone" is when Harry wakes up in the hospital after his battle with Professor Quirrell/Lord Voldemort to find that he succeeded in protecting the stone.
The resolution, which is also known as the denouement, is the last part of the plot. This is where the events are completely resolved and the story comes to a close. For example, Harry and his friends boarding the train and heading home for the summer would be the resolution.