For preparation, check whether the summary account is assigned in the settings.

1. Settings → Settings → Accounting
   In the field “Summary Account”, select “399: Income-Expense Closure”.

2. General Ledger → General register
   To close the financial year (accounts of classes 4 and 5), click the button “Closing of income and expenses”. In the opened window, specify the date on which you want to close the balance and click the Save button.
   After performing these steps, two main entries will be created in the General register – a credit and a debit transaction. The entry names will be YEAR_CLOSE-C (date) and YEAR_CLOSE-D (date). The created entries will be closed with an interim account.
   

   After registering the transaction, check how the general ledger was formed (Reports → General ledger reports → “GL summary with total accounts”).

   If an error appears, you can delete the entries: double-click on the entry, it will turn green, then open the document and click the Delete button.
   

   Note. In order for the balance sheet to show retained earnings, the obtained result should be transferred manually.