The Silly Ones and the Stupid Ones
Los tontos y los estúpidos (original)
A group of movie professionals go into a studio to, over a single day, read/test/live the story of 'The Silly and the Stupid'. Sitting around a table and instructed by the director, the actors show us the evolution of the creating process and how the characters, trials, indications, lighting or props that at first were just a story captured on a script, become a film, the great optical illusion.
Watch "The Silly Ones and the Stupid Ones" from streaming services Tubi TV, Plex Free released in 2014. It's a drama and family movie, and has a rating of 6.6 out of 10 from Imdb which is usually fine for this kind of movie, and is currently available to watch for free.