You can add or modify Web TimeSheet User and Project data from within the application by using the CSV Import feature. You may have set-up the CSV file using the "Web TimeSheet Data Import Utility User Guide.pdf" and so you have used the column header when entering the data.
If you choose to exclude a field names row (column header row) from the top of your import file, you will be allowed to choose the appropriate field names using drop-downs on the import preview page. The values you select will become the defaults for future imports without a header row.