To make listfile.bbs, you can use the file, listfile.bbs as a guide. 
 
The format of the file is as follows:
LINE 1 ------------ruler
Line 2 - N              The actual files that you make available to you
                        users.
 
Each line is broken up into fields. The fields are as follows:
Column 01 - 50         The full path name of the file to list.
Column   51            A space
Column 52 - 72         Description of the file.