Build an android application along with its corresponding backend code

I need a professional for creating an android application along with the backend code. The application mainly contains many experts from different industries, and there are few users who can call these experts according to the requirement of the user. Whenever a user will install the application, at that time they have to submit a little information regarding the name, place, country, email address, and phone number. After this, the user will undergo verification using the SMS. The home page must contain posters that will slide and also a search box where one can search for the expert, a navigation bar for going to the different sections, and a bottom navigation bar that will contain home, history, and Expert as the items of the bottom navigation bar. The user must pay the expert through the application with the help of a digital transaction, so for this digital transaction, need to add some external SDKs to use them. If once a user will call an expert at that time all the data regarding the number of minutes talked and the amount paid and the name of the expert consulted all this data has to be shown in the history section of the respective users. This is a brief description of the project.