An iPhone app

Hello, I would like to realize an application for iPhone or Android, or both, to collect information on the various electrical appliances installed in a commercial store. The app should have about 7 or 8 screens, the main ones are: - The "welcome" screen, standard with login and access menu to the various functions. This screen will list the various projects already existing and give the possibility to create new projects. - The "project" screen, allowing access to the different functionalities of a project: Visit, scenario, indicators, meeting, etc. - The "usage" screen, listing all types of possible materials with their use. - The "Visit" screen, the most important of the application. It is used during the visit of the store to register all the devices present. The screen should have a main work area covering 70% of the surface to create the different rooms present in the store. On the left there will be the materials to be placed in the rooms by drag & drop. These materials will be grouped by types and categories into several nested menus so that they can be accessed quickly. Each room created in the work area can be manipulated and modified, its parameters will be accessed and its visualization will have to adapt for a good reading of the materials it contains. - The "scenario" screen is like a calendar showing the use, or non-use (in% per day) of each device in each room over time. - The "display" screen will show charts of usage of the different devices per day, per month or per year, according to different criteria. One can therefore compare the data of a store with another and calculate different statistics. The application will have to access a database where all the information gathered will be recorded. The application will also retrieve from this database the various static data useful for its functioning like the usable materials, their type, etc. I draw your attention to the fact that the application will have to be ergonomic and visually appealing. What type of server should I take to run the application? Only an online database or a dedicated server with an application server? What is your settlement schedule? 20% on order and balance on delivery, or one payment every month or every week? Can you tell me how long it would take you to realize the first version of this application, for a demonstration, and also how much would it cost? Knowing that for development I will provide you with more detailed specifications. Thank you for your reply Regards