What goes into a film?

Preproduction - most important

Story

Scriptwriting

Storyboards

Location scouting

Casting actors

Financial backing

Budget

Concept art

Hiring film crew

Marketing

Costume design

Cinematography

Rehearsals

Make up artist

Health and safety

Directing

Prop design

Kit supply

Choreography

Production

Poster design

Lighting

Infrastructure

Cinematography

Catering

Transporting

Make up artist

Health and safety

Directing

Security

Acting

Computing

Marketing

Post production

Advertising

Editing

Soundtrack

General release

Marketing

Any film no matter the budget requires a huge amount of input from a variety of sources. Often preproduction is the stage you have to nail because if you get it wrong everything falls apart.

You have to organise what location to film in, what actors to hire, film crew and so many other things under a budget, you will have to feed a huge group of people, provide them with comfortability, entertainment and sleep in remote places, you have to keep them safe and also get them to do their jobs. This is the foundation of the film upon which everything else follows. 

All parts of film production also need to stay in touch with the underlying story, you have to keep it in mind with the directing to avoid angering fans of the original content but you also need to make it approachable for a wider audience. Most of this takes place in the preproduction but the director needs to keep the story in mind through the whole process.