Drama depends upon plot. The plot structure -- the arrangement of events and actions -- must be relatively simple so the audience, taking in the play over two or three hours, can easily follow the development of the conflict. To keep the audience involved, conflict is usually emphasized and conveyed through action and, most importantly, dialogue.
The structuring of the action is commonly described by the following terms: exposition, rising action, climax, falling action and denouement.
The exposition brings the audience up to date as quickly as possible, giving the setting (year, time of day, locale, etc.), the atmosphere (mood) and the main characters. Quite often minor characters are involved in the exposition preparing us for the entrance of the main characters. In Hamlet, the bleak midnight scene with the appearance of the ghost sets the tone while the conversation of those present renders the state of affairs in Denmark and provides a context for Hamlet's situation.
Once the exposition is handled (even before it is handled in some plays), an initial incident occurs to start the action rising. The ghost tells Hamlet of his murder. Conflict enters the action in the form of protagonist (hero) versus antagonist (villain), protagonist versus himself, or protagonist versus his environment. For example, Hamlet is in conflict with Claudius, with himself (should he avenge his father's murder by killing his mother and uncle?) and with his environment -- "There is something rotten in the state of Denmark" that allows a king to be murdered by his brother go unchallenged.
The highest point in the rising action leads to the climax, where Hamlet discovers the secret guilt of Claudius by the device of the play within the play.
After the climax, there is usually a fast falling off of the action. Hamlet's failure to kill the King at his prayers shifts the control to Claudius and Hamlet's downfall is assured.
The denouement is the final unravelling of the plot complications often involving an important discovery for the main character or a reversal of fortunes, either unhappy as in tragedy or happy as in comedy.
In the denouement everything that the author wishes to resolve is resolved. In many plays all questions are answered; all knots are tied securely. In other plays the denouement may be deliberately put on the shoulders of the audience where it is up to them to decide the answers to the play's questions.
The division of drama into acts and scenes frequently clarifies the plot structure, with each segment often having its own rising action and climax.
Some questions on plot: What are the main conflicts? What are their causes? How are they developed? How are they resolved? What expectations are aroused by the plot? Are they fulfilled? If so, how? If not, why not? Are there subplots? How do they relate to the main plot?