Break down one story multiple times
Or I should say, read or watch one story multiple times before setting to the task of breaking down.
This is the only way to learn story structure.
At first it might not be so obvious (it did take me three times of watching American Beauty to finally break it down). So read or watch it again. And again. And again. Set aside plenty of time to do it.
“But I don’t have the time!” I hear you cry.
Neither do I. Neither do any of us. We’re all living life that just keeps happening, no matter what we do.
Make time. It’s the only way. Make time for writing, and make time for studying how to write better. That is, read and watch like crazy. And once you read or watch something that really hit you in the gut, pause, and re-read and re-watch it until the story-meat falls off its bones, and you can recite the whole thing flawlessly when woken up in the middle of the night.