Use Jose’s tool: Trace Helper Utility for Epicor ERP 10 - ERP 10 - Epicor User Help Forum (epiusers.help) I think the post also shows how to turn on the trace.
Basically, tracing logs a bunch of the data moving around in the background. It dumps it all to an XML file, that you can view in a text editor, XML editor, or using Jose’s tool. The tool is nice because it collapses a lot of the XML garbage and just lists the methods in a drop down box.
Using the trace you can see all of the methods that fire, and then you can also see the data inside the method. Only turn the trace on just before you trigger the thing you are trying to trace, then turn of tracing as soon as possible after that. Otherwise, you end up with lots of extra recorded methods to step through to find what you need.