This document provides an overview and minimum script required for the billing threshold feature in Expert's Billing application. It discusses session goals of refreshing on the threshold feature, providing a minimum script, discussing pain points, and assumptions of basic script knowledge. The feature overview explains that the scripting language is BasicScript and the function returns a message indicating reasons for failure to prepare a bill. The minimum script provided is an example function that returns a test message including the prebill number. Session notes provide tips for experienced and novice BasicScript programmers on setting the prepare flag and where to go for help.