Hello, zazoom2020-outlo. I'm to help ensure you can upload Halifax transactions into QuickBooks Online.
If your bank is connected to online banking, QuickBooks will automatically download the transactions from the last 30 days. Since there's nowhere to find them, you may consider checking with your bank institution for maintenance issues. Here's an article for additional reference: What to do if you can't find downloaded transactions in QBO.
However, if you're manually uploading them, you'll have to ensure you're using a supported file type and format to upload them successfully in the system. QuickBooks Online supports 2 CSV formats (3/4 columns) when manually uploading bank transactions. The former has the Date, Description, and Amount. While the latter contains the following information: Date, Description, Credit, and Debit column.
I'm adding these articles you can read more about uploading bank transactions to QuickBooks: