There is a PDF on the web site.

on which website?? Been searching for 2 day's...only pdf i can find doesn't tell me much.
i've been trying all kind of things...cbjuice just doesn't accept my changed colums.

There is a PDF on the joomlacode web site. That is the best that we have had time to do.
On the main page, CBJUICE lists the available header fields.
If your fields are not in that list, then they are NOT defined in CB. Of course, the most common error is that the delimiter is NOT defined. Make sure that you specify the delimiter and SAVE it in the options for future ues.
The other error most often made is that the fields are not typed using the correct case or that there are special characters imbedded.