I appreciate the significance of having this historical data for your business operations, and I'm here to help you through the process of loading the data into QuickBooks Online (QBO), @DeerPointHOA.

Importing historical data into your QuickBooks Online (QBO) via a thumb drive is as easy as can be. Ensure you'll have to open the exported file from your thumb drive in QuickBooks Desktop (QBDT) to ensure it's formatted accordingly. 

The .qbb is a QB Desktop file format, that's why you can't open the file directly to QBO. If you don't have access to the QBDT program, you can download and utilize the trial version to complete the process. Afterward, proceed to migrate and import it into QBO. 

When you're ready to move a file from QBDT (Pro or Premier) to QBO, follow these steps:

1. Sign in as an admin to the company file you need to import.
2. Go to the Company menu, then select Export Company File to QuickBooks Online.
3. Click Start your export.
4. Sign in as an admin to your QBO company.
5. Select the Choose online company drop-down, and select the QBO company you want to replace your company file.
6. Click Continue.
7. Enter Agree in the text field, then select Replace.
8. Select Yes, go ahead and replace the data, then click Replace.

You can also read this article for the complete details: Move your QuickBooks Desktop file to QuickBooks Online.

For additional reference, you can use this article to understand how features and data move from QDT to QBO: Learn how features and data move from QuickBooks Desktop to QuickBooks Online.

Please know that we value your time and your business operations. If you have any further questions or concerns about the migration process simply click the reply button and we're here to support you.