The guide is the only written source that I know about. I’m not an emonCMS expert - my usual advice is to play with it and see if the numbers look sensible. If you log all the inputs before you do any processing, and you know approximately what you have running at any moment, it should be possible to verify (or otherwise) what you’ve set up is correct.
But - make sure you really know what you are measuring first, otherwise you end up in a massive tangle of confusion.