QuickBooks Self-Employed makes running your business hassle-free, with awesome convenience features like the Bank Feed. It's great to hear you're considering manually uploading your transactions in order to take advantage of this awesome tool. I'd be happy to explain how to format your CSV for a successful upload.
Here's an article that explains the step-by-step process of manually uploading your transactions: Add older transactions to QuickBooks Self-Employed. As explained in step number 7, you'll review the column headers and data first. Then, you're going to want to make sure the Date, Description, and Amount columns on the CSV match the columns and order in QuickBooks. The other column headers can be in any order.
If you're in need of any further assistance, our dedicated Self-Employed team is here to help. You can contact them via email, or in-product using the QB Assistant.