If you don’t want to track the chapters at all, I’d just schedule the resource with no divisions, and click on ‘worked on’ until the book is finished.
You can enter the past books like that, and if you don’t care about the dates they were done, I’d just mark it off as done and put a note in that the exact date the book was read was not tracked. If you know the dates and care, you can click beside the worked on / done location (I think on a triangle, going by memory) to see the past week… and then there is a little calendar button to add more dates to mark off.
