✅ Need help making classes

namespace BeatBooth.Classes.Pages
{
    public abstract class EnginePage : Page
    {
        public abstract void open();
        public abstract void close();
        public static EnginePage currentPage { get; private set; }

        public static void SwitchPage<T>() where T : EnginePage, new()
        {
            if (currentPage != null)
            {
                currentPage.close();
            }

            var newPage = new T();
            currentPage = newPage;

            GameWindow.Viewport.Content = newPage;
            newPage.open();
        }
    }
}

namespace BeatBooth.Classes.Pages
{
    public partial class GameMainMenu : EnginePage
    {
        public GameMainMenu()
        {
            InitializeComponent();
        }

        public override void open()
        {
            Console.WriteLine("Open");
        }

        public override void close()
        {
            Console.WriteLine("Close");
        }
    }
}