If you exported the balance sheet into Excel format, skip this step. Select the exported file and click "Open." Because the file is in a recognized CSV or XLS format, it will open automatically.

Although a running balance is commonly maintained on the same Excel worksheet as the debits or credits, you can also keep a running balance with figures that reside on different Excel sheets.

The article How to calculate conditional subtotals in an Excel revenue sheet uses simple expressions, a function, and a conditional format to display a daily balance in a revenue sheet.