Entry point into plugin with Batch Tasks API

I am making progress with the Batch Tasks API, but I still don't understand how Studio enters my plugin code. There must be one or more methods that are called, but I don't see where that is defined.

I also wonder exactly what parameters Studio passes to my plugin code? If all batch tasks are designed to operate on files, then there must be a list of input files.

Can anyone point me in the right direction? Here is the Batch Tasks API reference: http://producthelp.sdl.com/SDK/BatchTaskApi/2017/html/cb547244-58ba-f143-931d-b04b3d7f5922.htm

Thanks,

Gary