The backbone of an accounting system is the chart of accounts. Every country has its own chart of accounts depending on the business type or yearly turnover.
It is recommended you start the accounting system from the new financial year. You just need to import the balance sheet; it is advisable to not work on importing the old accounting entries.
Keep handy the last balance sheet to import. If you have an unaudited balance sheet before the audit is complete, you can skip the import process and start working with the new financial year entries in the accounting module. Import the balance sheet as soon as you get the final balance sheet after the audit is completed.