Every film starts with development. The idea is thoroughly researched, access is secured, the budget is written and a treatment is produced that clearly presents the vision and narrative for the film.
In pre-production every aspect of creating the film is designed and planned. From locking locations and contributors to hiring crew and kit, scheduling the shoot and addressing legal concerns.
Production is the shoot. At the end, you've got your rushes to start editing.
Post-production involves editing the film, clearing music and archive, adding voice over, sound effects and graphics. Once a film is locked it will be graded, mixed and prepared for distribution.