On my website we send out payments every week and for accounting we need a big invoice for all of them.
The script wants to connect to the site database and let us download csvs/excel files for each month which just lists each payment and the users name, email address, amount, payment method.
To find each payment the script needs to look in table 'kk_transaction' and in field 'reason' it wants to have 'withdrawal_paypal' this would then find all withdrawals ever. Then to match a withdrawal to a user account you look in the row of the withdrawal in database in field 'user_id' and match that to a 'id' in table 'kk_user'
Its not a massively complex project, but not super simple. Should not take to long.