If you have already imported files into Xero, the format may need to be reset.
If this is the case, to reset the mapping options you have set up, you can go into:
Manage Account > Edit Account Details > Statement Import Options
and edit the mapping details.
If you find that you are unable to make the required changes in this screen please rename one of the column titles in the CSV file.
For example you could rename Date to Dates which will then force Xero to prompt for full remapping of all columns.
Full instructions are included in the Help Centre link: