How to connect npm plugin?

Question

css

Hello!
I'm trying to understand how the npm plugin https://github.com/zgreen/postcss-critical-css is connected and executed .
I put it in the project (npm install postcss-critical-css --save), but I don't understand how to run it and where to set the parameters .
I looked in the package.json of the project itself (I thought it would be clear from his example how to do it) and did not understand how it works and what it does.
If you can't answer in detail - throw off the link where it will be told about it.
Thank you all for your time, I hope you understand :)

Answer 1

The repository has a folder /example with a simple example.
Configuration parameters are passed by the object during initialization.
Link with detailed answers to all questions.