How to write a complex SciFi plot without going mad

Here’s my revelation of the day: There are two stories to a book:

• One is the (hi)story. The whole that could be explained in chronological order. No tempo, just facts. History.
• The other the plot. It has three acts and structure. Starts with a hook, and ends with a climax.

Those don’t need to match. They need to overlap. The plot is contained within the larger story.

I guess, I finally understood the story vs plot distinction. One is flat, objective, boring, the other is has dramatic intensity and emotion.

So how to write a complex SciFi plot without going mad¹:

1. Write the (hi)story first. Do not worry about structure. Just facts that are consistent.
2. Then figure out a plot that fits within that story.