I'll share insight on your query about the trial balance in QuickBooks Online (QBO).
The Trial Balance report summarizes the debit and credit balances of each account you have on your Chart of Accounts at a time. With that said, there isn't a need to delete the entries for November and December 2019. You have the option to set a date range when you run the report.
If you'd like to import trial balance into your QBO company, see this article: Import trial balances. It's a detailed step by step guide on how you can upload a trial balance to your QBO company.
Utilize the comments section if you have other questions. I'll take care of them for you.