I can help you in generating a sandbox test company file, Heidi.
To begin with, you'll need to set up and create a developer profile. Following the creation, you'll automatically get a sandbox company. Moreover, you can make up to 10 sandbox companies.
To produce a new one, please follow these steps:
Log in to your developer account and go to the API Docs & Tools tab.
Select Sandbox and click the + Add a sandbox company option.
Choose QuickBooks Online Plus or QuickBooks Online Advance. If you've chosen QuickBooks Online Plus, picking your Country on the dropdown is a requirement. When created, the Country is unmodifiable.
Thanks for coming back and asking additional questions.
Using a trial version of your QBO may be better off for you and your business when testing out a new chart of account. The trial version allows you to import and export your own data while trying out features and much more.