[Koha] Keyword to MARC and Koha to MARC mapping documentation?

[Elaine Bradtke]

Getting closer to actually running Koha!
I'm installing 3.2., because I've been told it's more useful for the
type of library (small, specialized, complicated interrelationships)
catalogue we've got.
One of the things I want to do is to be able to search on and link to
our 001 fields (control number - these were generated from our
original catalogue system). This would enable me to make use the
linking ability of the 774 field without having to import everything
first so I have the 999c Koha number, and then going back and adding
these in where needed.
I /think/ the way to do this is through keyword to MARC and Koha to
MARC mapping.  But I can't find any documentation that explains what
these features do, or how to use them.

 I found that in the Koha to MARC mapping, biblioitems level there is
the lccn	010	a	LC control number
We don't have LC control numbers for any of our material at the
moment. If I go in and change this to 001 a it doesn't change the
label - which makes me suspicious that I haven't done the correct
thing.

Is there a way to add a MARC tag to the biblioitems list? Have I
missed a step? Is that where the Keywords to MARC comes in? I could
really use more information on these features.

I feel like I'm blundering around in the dark in the midst of some
very delicate machinery, and I don't want to break anything.
Thanks
-- 
Elaine