Call Center - php

I need to use PHP, and I am creating a piece of software that can be used for a call center to take mail orders. So, a customer will call and a member of staff will answer it and process the order. But the main aim of the system is to incorporate scripts, which the Staff can use as prompts when dealing with customers. For example, it should come up on screen what the yhave to say. "Good Morning Sir thank you for calling XYZ", Also clicking on special buttons - will bring up todays' speial offers The system must be able to add products, price, colour etc and total it. ** Also one big thing would be if you could annontate the coding so that I can understand it I will send you some more documents as well. If you need any more help please dont hesitate to contact me. i need it asap Best Regards