The film jumps through major events in French history that shaped Napoleon. For example when he becomes the emperor. They spent maybe five minutes covering that. It’s hard to follow the arc of his rise with only devoting several minutes that such major events. But then spend half the run time to his marriage.
The film still manages to get this wrong. Napoleon needs an heir and it’s a major driver for he divorces his wife. But the child never features.
Watch the trailer. Read Wikipedia.