To start, you need to add subtypes to you General Ledger accounts. There are two subtypes. Subtype 1 will be either an asset, liability, or equity.  Once you have selected subtype 1, the options for subtype 2 will be determined.

subtypes

Once you have selected the values for subtypes 1 and 2, you will need to go to your reporting tool. Open your balance sheet report and click the customize button. Once in the customize screen, just drag the subtypes into the body of the report. Then hit run.

classified_balance_sheet