[Koha] How to link the field

  Dear frenz hi I am using koha window version. following is the specifications Koha version 2.2.4 OS version Microsoft Windows XP [Version 5.1.2600] Perl version5.008007 MySQL versionmysql Ver 12.22 Distrib 4.0.26, for Win32 (ia32) Apache version Since I am handling a film library, we have the documents like video tape contains so many subjects within a single tape. So I want to create a new field of time duration in Cataloguing module. I also want to show this field in Opac. So anybody plz tell me how to create a new field and how to link it with opac module so that it could be shown during the catalogue search. Thanx in advance regards Librarian Jahangirabad Media Institute Barabnki U.P. India Ph. 05248-243372