A first guy write a story, but has to format it following some rules and be clear to everyone involved in the process.

Someone reads all the story and take notes about what is needed (ie: the formatting says that the character uses a cellphone, so we have to get one)

Actors get casted. With the previous list we knows what sets/accessories/etc we need to buy and or create.

The next step is big : every step of the filming is planned according to who is available/what set is available/etc…

That’s why not every movie is shot in chronological order, ie: if the characters leave Toronto for Spain and then come back, we shoot all the Toronto scenes in one block and then the Spain ones.

For the shooting the actors and the crew rehearse and then we shoot the scene, we reshoot the same scene as long as necessary for the editing phase, a large shot with everybody in it, close-ups, face-to-face shots etc…

Someone on the set is charged to make sure to note which takes are the good ones, it helps the editor later.

When everything is shot, the sound takes are synced to the video takes and we can start editing the movie. At some point the movie is "picture locked" it means that the shots, their length and order won’t move anymore and we can finally put music, special effects, sound effects, color correction, etc…

After all this steps we have the complete movie. Hope it helps.