<p>can anyone provide/refer a proper OO type helper class for managing a singleton of the SessionFactory and then also for managing Sessions?</p>

Sure, this is what I used when I was getting started with NHibernate:
Session Factory
```
```
public class BaseDataAccess
{

  protected ISession m_session;

  public BaseDataAccess()
  {
    m_session = NHibernateHttpModule.CurrentSession;
  }

  public static ISession OpenSession()
  {
    Configuration config;
    ISessionFactory factory;
    ISession session;
    config = new Configuration();

    if (config == null)
    {
      throw new ArgumentNullException(nameof(config));
    }
    if (factory == null)
    {
      throw new ArgumentNullException(nameof(factory);
    }
    if (session == null)
    {
      throw new ArgumentNullException(nameof(session));
    }

    config.AddAssembly("My.Assembly.Here");
    factory = config.BuildSessionFactory();
    session = factory.OpenSession();
    
    return session;
  }
}
```
```
Let me know if that helps.