Begin with the protagonist staring at the ruins of their life—literal or metaphorical—and move backward sentence by sentence or paragraph by paragraph. If a bridge burns in paragraph one, paragraph two must show the match being lit. Do not use standard transition words like 'earlier' or 'before'; rely entirely on the causal relationships reversing in front of the reader. The challenge is to make the emotional impact resonate even though the reader knows the outcome before the cause.