Android-flutter application update

I need to update the Android application. I would like it to be designed and built. flutter programming language it works, but i need some modifications first, I need a system to search for videos by name, the videos are on Google firebase-storage then I need the application to have a login system, that I can, create users, Delete users,, suspend users, then I need you to modify something in it, the application plays the videos within the application itself, I need the application to ask me which application the user wants to open the video on, for example when I'm going to open an image the device asks if I want open in the Google photos app or in the gallery app, or in other apps that are installed, I want the same thing, that the app launches the video to the other media player video app open the video This project is just a prototype project, so you don't need to work on the design, if you are going to do any design, make the design as simple as possible My application is not yet published