Mass Data Import - Ivoices

Hello,

I work for a courier franchise. Invoices are created by the central office towards the customers I serve. Not all invoices. Just the ones that are meant for account holders. That is people who do a lot of volume and have to pay according to their monthly traffic. I can’t follow their traffic through my office so that is monitored from the central offices. They send me the invoices every month in a sheet so that I know which customer needs to pay what. At the moment I have to manually create each invoice by hand which takes the better part of the month and then send them to my customer by email through dolibarr. That is the process I need automated.

Is there a guide on how to get started with creating modules in dolibarr? I suppose that if I could find the php code that handles exporting, I could use my php skills to create a module that handles importing.