The iterationData value can be like it is in that example or that same array format in a local file and referenced in iterationData using require('data.json').
You could also use a URL, as a string which points to something that returns the data in that JSON format. Basically, that’s the format it needs to be in, how you reference that in the object is the thing that will be changing.
A CSV file can also be used as a source of data.
If the readme doesn’t make sense or the example is not giving you the necessary information you need to use the library, please do file an issue on the repository.
I feel like I’ve told that a few times now 