What does game design mean? And what should the designer do?

Question

Android

You need to develop a design for a specific game. Let there be some kind of arcade with 3 characters and 3 screens, and the game play itself has several different backgrounds. There are also about 10 items.

1. What should a designer imagine if he undertakes such work?
   
2. What should be the files, what should be their structure?
   
3. What format should they be in?
   
4. In the case when I develop a design in the application is it better to do and which program is most often used?
   
5. A very important question is how much does such a service cost?
   
6. Also, the price of animation, is it included in the total amount of the service or separately, and if separately, how much does it cost?
   

Answer 1

A very important question is how much does such a service cost?

You take the amount you want to earn per month and divide by the number of hours you work to get your hourly rate. You assign time-based payment per hour/day/week/same month. If you need a fixed amount, then you estimate how much time (hours) you will spend on the project and multiply by the hourly rate.
How else? No more, since there is no experience in this area (judging by the question). Finish this project and you will better understand how much a pound is worth.

Answer 2

The Terms of Reference will answer questions from the first to the third inclusive. Every game and every order is different.
4 - depends on 3 points. Usually adoba products are used. Although the question is somehow strangely worded.
5 - depends on the timing, level, size, complexity, etc.
6 - animations of what? background? character? Character 2d, 3d? Spritesheet animation, or something else? Well, in general, you understand. Whether it is included or not - again - depends on the Terms of Reference.