From the “New content” menu, choose a Mail form. In the “Configuration” field, you enter a form definition. The format for form definitions is defined in TSRef:

http://typo3.org/documentation/document-library/doc_core_tsref/FORM/

Here is an example form definition:

Whenever a form is submitted, the form data will be appended to the CSV file configured in TypoScript, by default this is “fileadmin/csv(pagename}_{month}.csv. If Page is the name of the page the form data was submitted to and Mon is the current month, the default filename will be.

fileadmin/csv/Page_Mon.csv

If you download and import the file

Note that the extension automatically creates CSV columns from the fields in the formmail, this means that if you alter the form, the extension will add more columns but never remove any, just leave the fields empty. this way you can change the form without loosing any data in your csv-file