how do I set the date on a new account for the ballance sheet for the past

Welcome to the Community forum, @melmoman! To provide an accurate solution, I'd like to know more details about your concern in QuickBooks Online (QBO).

If I may ask first, have you recently created a new account in the Chart of Accounts (COA) and are trying to reflect a starting balance for this account on the Balance Sheet as of a past date?

Any additional information you can provide will help me understand your specific situation and offer the most relevant advice. If possible, a screenshot of what you're seeing would be extremely helpful.

On the other hand, if you want to customize your Balance Sheet report to show past periods. Here's how:

1. Log in to your QBO account.
2. Go to Reports then search for and open Balance Sheet.
3. Choose Custom dates from the Report period dropdown.
4. Pick a historical date on the From and To options.
5. Hit the Refresh report icon.

For detailed information about the Balance Sheet report, you may want to navigate through this article: Run a Balance Sheet report in QuickBooks.

I hope this helps you, @melmoman. If you have any questions while working through this process, feel free to post here again.