Let's make sure you'll be able to bring transactions manually in QuickBooks Online without connecting your bank account.
We can use the Web Connect feature to manually upload transactions in QBO. It's how we can bring entries without linking your bank account to your book. First, download them from your bank. Here's how:
Sign to your bank's website.
Follow your bank’s instructions for how to download transactions to your computer.
I would recommend saving the file where you can easily find it.