I'll share information about importing files in QuickBooks Online (QBO), Philip.
To begin with, please make sure that you've already added your bank account to QuickBooks so you can proceed with importing files from your bank.
However, if you have already added a bank account to your QBO account, we need to ensure that you don't import the data into a subaccount, as this is a current limitation.
Moving forward, here's how to manually add your bank transactions:
Go to Transactions, then choose Banktransactions.
Click the blue tile for the account you want to upload the transactions.
Select the Link account dropdown, then select Upload from file.
Select Drag and drop or select files and select the file you downloaded from your bank. Then, select Continue.
In the QuickBooks account dropdown arrow, select the account you want to upload the transactions and select Continue.
Follow the onscreen steps to match the columns on the file with the correct fields in QuickBooks. Then select Continue.
Select the transactions you like to import. Then select Continue.