I'm here to help you with adding your bank account in QuickBooks Online, @Georgie2.

Adding your online banking account in QuickBooks Online (QBO) is safe and secure. The connection for online banking is always read-only so that no one can use any of your information in our product to move any money. We don't sell, rent, or share your information with third parties for their promotional use.

When adding your online banking account, you need to use the credentials you're using in your online banking account. For detailed guidance on how to add your bank account in QBO, check out this article: Connect bank and credit card accounts to QuickBooks Online. 

In case, you're having trouble adding your bank, here's how to add your bank transactions in QBO: Manually add transactions to accounts in QuickBooks Online.

Let me know in the Reply section if you need further help to add your bank account or anything else. I'm always here to assist. Have a great rest of the day!