I am looking for an expert in all the processes involved in mobile app design, development and launch with specific knowledge of selling access to content. The app needs to have a reader for flashcards and be interactive (that may not be the correct term) with user sign-in. I need to understand what would be involved in creating the back end files etc to make it work - sorry I'm not sure of the correct terms - hence this request. I will not be developing the app myself so also need to understand how to go about getting a designer/developer to create this app for me. The design would be based on the website that I am creating on Wix. Many thanks!