//Variables needed for calculations:
private double principal = 1000.00d;
private double apr = 2.99d;
private int numyears = 5;
private DateTime date = DateTime.Now;

        /// <summary>
        /// Build the report with ExcelTemplate
        /// </summary>
        public void GenerateReport()
        {

            // Create an instance of ExcelTemplate
            ExcelTemplate xlt = new ExcelTemplate();

            // Open the template workbook
            string templatePath = @"..\..\templates\LoanCalculatorTemplate.xlsx";
            xlt.Open(templatePath);

            // Pass the data to the BindCellData method
            // and specify the data source name

            DataBindingProperties bindingProperties = xlt.CreateDataBindingProperties();
            xlt.BindCellData(principal, "Principal", bindingProperties);
            xlt.BindCellData(apr / 100, "APR", bindingProperties);
            xlt.BindCellData(numyears, "N", bindingProperties);
            xlt.BindCellData(date, "Date", bindingProperties);

            // Call the Process() method to populate the template with the data source values
            xlt.Process();

            // Save the report
            xlt.Save(@"..\..\Output\LoanCalculator_output.xlsx");
        }
    }