How Is The Movie "1917" Shot And What Is The Secret of Continuous Shots

How is cameraman work arranged in the movie "1917"? Why did Sam Mendes decide to make a film about the First World War in such a way as to create a sense of one continuous shot? How was a long shot used in cinema and what tasks does it perform in "1917"? And why the film was not just a technically perfect creation of the cameraman Roger Dickins, but a very personal and humanistic statement?