Uploading Spreadsheet

Trying to create orders through a spreadsheet. I have tried multiple ways, and get errors no matter how I attempt to do it.

One spreadsheet gives me an error of “You have a blank column that has been edited.
Please delete that column and re-upload your spreadsheet.”

So I tried downloading to excel, adding files, and then re-uploading it. With that I get an error of “You have a column which is not recognized: File Number.
Please make sure that the column names match the order field labels exactly (without the word order).” But I am using the same sheet that I downloaded, so how is it not recognized?