Back in the old days, you used to actually have to cut up and tape film together to make a movie. Nowadays, of course, everything is done with expensive software on computers.
Side Note: I HATE it when people use the word "film" when shooting video. You cannot "film" anything with a video camera. It's impossible. Just as you can't "run to the store" in a car or phone someone by dialing a brick. Any idiot with a camera can shoot a video (though not necessarily well). Shooting and working with film takes a tremendous amount of skill and know-how - which is probably why it's a dying medium.