Hi there, mick9.
It sounds like you've just connected your bank account. Let's add the missing transactions.
Normally, banks will only send transactions for the last 90 days. To add the old ones, you can download them from the bank's website. Then, upload them to the Banking page in QuickBooks. You can refer to this article: Manually upload transactions into QuickBooks Online.
You can also check about assigning, categorizing, editing, and adding your downloaded banking transactions.
Please don't hesitate to go back to this thread if you have other questions about your missing transactions.