using SoftArtisans.OfficeWriter.ExcelWriter;
...
ExcelTemplate XLT = new ExcelTemplate();

XLT.Open(Page.MapPath("//templates//part1_template.xlsx"));

DataBindingProperties dataProps = XLT.CreateDataBindingProperties();

object[] valuesArray = { "FY 2004", "Canadian Division", "Research and Development" };
string[] columnNamesArray = { "FiscalYear", "Division", "Group" };

XLT.BindRowData(valuesArray, columnNamesArray, "Header", dataProps);

DataTable dtTop5 = GetCSVData(Page.MapPath("//data//Part1_Top5Expenses.csv"));
DataTable dtAll = GetCSVData(Page.MapPath("//data//Part1_AllExpenses.csv"));

XLT.BindData(dtTop5, "Top 5 Expenses", dataProps);
XLT.BindData(dtAll, "All Expenses", dataProps);

XLT.Process();

XLT.Save(Page.Response, "Part1_Output.xlsx", false);