How do I enable an in app purchase that will display a new screen?

I am trying to build an app where there is a premium version and a free version. When someone purchases the premium version, I want a new screen to show. How do I do this.

Code

import SwiftUI



struct ContentView: View {

    var body: some View {

 

        VStack {

    Link(destination: URL(string: "https://www.icloud.com/sharedalbum/#B0tG4Tcsmu6ATjR")!) {

                VStack {

                    Image(systemName: "paperplane")

                        .font(.largeTitle)

                    Text("Click here to get wallpapers!")

                        .accentColor(Color.white)

                        .background(Color.black)



                        }

                    }





                    }

                }

            }



Premium Code

import Foundation



import SwiftUI



struct Premium: View {

    var body: some View {

 

        VStack {

    Link(destination: URL(string: "https://www.icloud.com/sharedalbum/#B0tG6XBubu4jvR9")!) {

                VStack {

                    Image(systemName: "plus")

                        .font(.largeTitle)

                    Text("Click here to get Premium wallpapers!")

                        .accentColor(Color.white)

                        .background(Color.black)





                    }

                }

            }

        }

    }

How do I enable an in app purchase that will display a new screen?
 
 
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