Exposition is the information needed to understand a story.
Complication is the catalyst that begins the major conflict.
Climax is the turning point in the story that occurs when characters try to resolve the complication. Resolution is the set of events that bring the story to a close. It's not always a straight line from the beginning to the end of a short story. This shifting of time is the way we learn what happened and why, and it keeps us interested in the story. But good stories always have all the plot elements in them.