NAV 2017- Positive Pay Modifications

Hi. I need to modify the file output of one of the two "stock" positive pay definitions. In past versions I just edited the simple code that spit out the file. But in this version it's all wrapped in configuration stuff. I can't find any real documentation on the specifics of the field definitions - and I'm hoping I don't have to modify code too much. I've looked through it and it's a bit ... dense. (Like me.)

Any pointers to more complete documentation of the field definitions out there anywhere?

Thanks!