App.cs

public partial class App : PrismApplication
{
        public App(IPlatformInitializer initializer = null) : base(initializer) { }

        protected override void OnInitialized()
        {
            InitializeComponent();

            var tabs = CreateTabs();

            NavigationService.NavigateAsync(tabs);
        }

        private string CreateTabs()
        {
            var showingNowTab = $"{KnownNavigationParameters.CreateTab}={Screens.ShowingNowNavigationPage}|{Screens.ShowingNow}";
            var categoriesTab = $"{KnownNavigationParameters.CreateTab}={Screens.CategoriesNavigationPage}|{Screens.Categories}";
            var aboutMeTab = $"{KnownNavigationParameters.CreateTab}={Screens.AboutMeNavigationPage}|{Screens.AboutMe}";

            return $"{Screens.MoviesHomeTabbedPage}?{showingNowTab}&{categoriesTab}&{aboutMeTab}";
        }
        
}