[Koha] School Library Management (loans, returns ,account handles...)

[Osgaldo Suanzes]

Hi
My wife is working in a School here in Spain And she is responsible for the
School Library.
There are sometimes too many children asking at the same time for loaning
books, without a computer!
So she asked me if I could managed to setup a Library Book Managment System,
Something that
with a Barcode Reader she could Inventory the books and handle the Loans
and returns of the Kids. Everyone is telling me that Koha is the way to go,
but I must admit I have
no clue about EAN and ISBN and if Koha supports Loans and returns and
such....
I highly appreciate any hint
I would prefer to build this upon Debian

here a few questions also:
    What exacty is in the Koha-CD.iso file? should I better download the
Aplication tar.gz?(smaller download)
    Who can help or tell me on how Koha must be modified to match our needs
(School Library Loans, returns, User administration, inventory trough a
barcode reader?(if its possible)

Im pretty sure this must be asked a lot of times, Im sorry for this. but I
need some guide

            Thanks in advance.

                                Osgaldo.
PD: Sorry for the bad english!