Hi Jeyakumarbics1, You don't need to create new template for TimeSlotItem. You need to attach function to MouseLeftButtonUp of RadScheduleView and in body of this function you need to create and execute CreateAppointment command.
private void ScheduleView\_MouseLeftButtonUp(object sender, System.Windows.Input.MouseButtonEventArgs e)
{
System.Windows.Input.RoutedUICommand createAppointment = RadScheduleViewCommands.CreateAppointment;
createAppointment.Execute(null, this.ScheduleView);
}