[Koha] import records and map field to marc

[Jochum van der Heide]

Hi,

I'm about to import our 6000 records from an old DOS based library system 
to Koha 3.0. I understand the best way to do this is using the 
misc/migration_tools/bulkmarcimport.pl tool after creating the marc file 
from csv with MarcEdit. Currently all the fields I could export from our 
old system were the following:

Catalogue Record Number	(barcode field?)
Title			245a
Series			440a
Author			100a
Subject			650a
Call number (local)	082ab
ISBN			20a
Publishing - Name	260b
Publishing - Place	260a
Publishing - Date	260c
Extra			653a?
GMD (Item type)		942c

What is the best field to use for the barcode? Also the Extra field has 
some additinal info about the subject of the book. I was thinking this 
would perhaps fit in 653a.

I noticed that by default there are a number of MARC fields mandatory. For 
example, what is the 000 leader field used for and why is it mandatory? 
Should I be using those fields or is it save to not make them mandatory?

BTW, are there any instructions available on using the bulkmarkimport tool?

Thanks,

-Jochum