I guess the main premise is that the authors believe it’s possible to accurately calculate the amount of labour required to deliver goods and services and that you could use these measurements to reflect the need for raw materials, labour-power etc and as a result deliver goods and services on a schedule that’s based more closely on consumption rather than profit whilst reducing labour time.
There’s a fair bit of other stuff in there as well about a more radical democracy based on a sort of digitized direct democracy, socialized medicine and childcare.