[Koha] Batch record modification of Biblio items such as 650 subject tag!

Hi, Namaskaar! I would like to seek help regarding Modification of Batch records using Tools Menu Option : Batch record Modification, and modifying the record(s) with the help of MARC Modification template. Kindly provide me a link to By watersolution video on the above subject or any other proven solution to understand and fix the above problem. Thanks With regards Kuppuswamy Librarian IIAEM Jain University,