//For complete examples and data files, please go to https://github.com/groupdocs-assembly/GroupDocs.Assembly-for-.NET
//Setting up source html template
const String strDocumentTemplate = "HTML Templates/Common Master-Detail.html";
//Setting up destination html report 
const String strDocumentReport = "HTML Reports/Common Master-Detail Report.html";
try
{
    //Instantiate DocumentAssembler class
    DocumentAssembler assembler = new DocumentAssembler();
    //Call AssembleDocument to generate Common Master-Detail Report in html format
    assembler.AssembleDocument(CommonUtilities.GetSourceDocument(strDocumentTemplate), CommonUtilities.SetDestinationDocument(strDocumentReport), DataLayer.PopulateData(), "customers");
}
catch (Exception ex)
{
    Console.WriteLine(ex.Message);
}