What's a story climax?
One way to look at a story is as a clash between two opposing forces.
For example:
•The character's temptation to steal her sister's inheritance vs. her conscience, which tells her it's wrong
•Home team vs. away team
•Bachelor Number 1 vs. Bachelor Number 2
Suspense comes with the reader's uncertainty about which side is going to win.
The story's climax is the definitive confrontation which determines the winner. It's when the detective and the killer finally face off in the dark basement, and the reader knows only one is going to come out alive. It's when Bachelor Number 2 bursts into the church to stop Bachelor Number 1 from marrying the bride. The climax is the moment the reader has been waiting for. After the climax, things settle down in one direction or another, and you have the story's resolution.