I can provide details about manually downloading bank transactions in QuickBooks Online (QBO).
When connecting your bank account to QBO, the system will automatically download the last 90 days of transactions. To manually download the prior month, please refer to these steps:
Sign in to your bank or credit card website.
Follow the instructions on how to download the transactions to your computer.
Check the date range for the download. It should be at least one day before the date of your oldest transaction.
Review the file format and size (350 KB). Ensure to use (QBO) format.
Once done, log into your QBO account.
Go to the Banking or Transactions menu.
Select the Banking tab.
Click the blue tile for the account you want to upload the transactions.
Select File Upload from the Update drop-down arrow.