Fixing the column mapping

On the "Check the columns" screen, each sheet has a preview with the chosen columns highlighted. Change any role (question, Yes/No answer, written answer, comments) from its dropdown, or tick "Skip this sheet".

Each column can have only one role. Columns are shown by letter, so you can pick them even when a sheet has no header row.

Nothing is imported until you press Import, so you can go back and forth safely.