steps involved in making of a film

First of all I will tell you the sequence according to my knowledge.Since I am not the expert in film making some steps may be missed here but generally it takes following steps:
1.First director of the film, according to whom each and every scene in the picture is filmed, finds the good story.
2.Then he approaches to the producer, the man who will finance the movie first and then collects the profits accordingly, sometimes director may itself produce the film.
3.Then director and producer will decide on cast of the film.Cast of the film means the people who are working in film.
4.Then they will approach to the appropriate actor and actress and discuss the story with them.If actor/actress finds it interesting then they will sign the film against previously decided amount and give the shooting dates to director.
5.After that they will decide on music composer,lyrist and song writer so that all this work should be ready as early as possible.
6.Them shooting of the film starts. Choreographer, director,song writer and lyrist sit and decide on the place of song in the film and its shooting locations and dance moves.Choreographer is responsible for the dance moves in the songs.
7.After completing all the shooting the work of editing ,sound mixing etc, which is called post production work starts.Though it is post production work it is very important for the success of the film.Editing is the art of cutting unnecessary scenes in the film which will not affect the track of story and makes movie fast and interesting.So this work is also very important.
This is general procedure in movie making.
Director and its staff is responsible for coordinating all these sequences and people involved.
You are right in the sense that some scenes are filmed irrespective of the flow of story.