You must create a new account and password for yourself, if you have not done that yet. Then (after getting an email), log in.
In Nelli, push "Export to RefWorks" button .
In the RefWorks page, log in. Then you can see what has been imported. References can be grouped etc in RefWorks, but this example illustrates only how to get the BibTeX entries.
Choose Bibliography tab. There, choose BibTeX as the output style and choose the format for the file (e.g. text for emacs). Then you can choose eihter your whole reference list stored in the RefWorks or you can choose those references you want to get in BibTeX format.
Add a search key for the entry. You can change and add your own fields for the BibTex. For example, if you know the full name of the author, you can ad it, and if you want to write your own comments, add "annote" field to the entry.