This is an interface:

[ServiceContract]
public interface ISectionFacts
{
        [OperationContract]
        DataSet GetSectionFacts(int SectionFactID);
}

This is DAL
 public class SectionFactsDAL : ISectionFacts
 {
      public DataSet GetSectionFacts(int SectionFactID)
      {
             write down the code here to call the sp and return dataset;
      }
}


Thisis the service class

public partial class SectionsService : ISectionFact
{
// Call the DAL function from here
public DataSet GetSectionFacts(int SectionFactID)
        {
         try
            {
                SectionFactsDAL objDAL = new SectionFactsDAL();
                return objDAL.GetSectionFacts(SectionFactID);
            }
            catch
            {
                throw;
            }
       }

}
This is the service which reference will be added in the project

public partial class SectionsService : ISectionsService
    {

        #region ISectionsService Members
        #endregion
    }



Now bulid this and run the service and add the service reference in the application by Add Service Reference and run the application. this is the SOA Architecture.