You can alter the field name, data type, and size by selecting the field from the list of Available Fields, typing in the new Field Name in the space provided, selecting the data type from the Field Type drop-down list, typing in the desired size in the Field Size box, and pressing the Apply Changes button.
To alter the Settings for the import, press the Change Settings button to revisit the Settings area.
You can also choose which fields are imported by checking or un-checking the box next to the field name.
NOTE: The First Row setting will be taken from the First Row setting in the Settings dialog. However, you can alter the final setting here.