The short version
Every professional motion project follows the same six stages. Knowing them makes you a far better client.
What is really going on
Clients who understand the stages give feedback at the right time, which is the single biggest factor in project quality.
Each stage has a different cost of change, and knowing that changes how you use it.
The stages exist to make the expensive parts of production safe.
How to handle it
Brief and discovery: agree objective, audience, message and constraints.
Script and boards: decide structure and shots. Style frames: approve the look as stills. Animatic: approve pacing at final length.
Animation and finishing: build, light, render, grade and deliver every format.
The takeaway
Feedback is cheapest at boards and most expensive after render. Use each stage for what it is designed to decide.