The story or PLOT of a play can unfold in several different ways:
Climatic -- The action leads to ONE BIG SCENE, one climax, where all the themes and conflicts come together on stage and explode? The scenes don't have to be strictly chronological (where the time of scene 2 is after scene 1 and before scene 3). Scenes can be out of sequence, but one will still be the BIG moment? Obviously this climatic scene will be in the latter part of the play, usually the last or next to last.
Episodic -- The action unfolds as a series of episodes all connected but perhaps out of chronological sequence. Most scenes are of equal significance; that is to say, no one is necessarily more climatic than another though some episodes may have their own mini-climax.
Circular -- Similar in structure to Episodic but the last episode ends up similar to the first so the play can just start all over again. Popular in Theater of the Absurd where human action is trivialized and life is seen as an endless repetition of similar events.
Note: Some plays mix these different structures.