view sheet on first launch

Hi

I'm trying to display a sheet when the app first launches, similiar to when you upraded iOS to 13 and tapped say reminders.

But I'm struggling to get with working with SwiftUI, here is a snippet of the code. It essentially crashes the app.

import SwiftUI

struct ContentView: View {
    @State private var showingSheet = false

    var body: some View {
       return self.sheet(isPresented: $showingSheet) {
            RegisterHome()
        }
    }
}

struct RegisterHome: View {
    var body: some View {
        NavigationView {
            Text("Register")
                .navigationBarTitle("Register")
        }
    }
}

Any thoughts would be very much appreciated.

Thanks, Craig