The prologue is its own book, and was originally NOT being put online. It was just going to be a printed book, however I got a lot of people wanting it online also, so I agreed to post it on dA and other places for it to be seen and downloaded. However I have others who have said they want a printed copy still, so now I'm doing both. It's taking a lot of effort to coordinate both releases.
As I said, the Prologue is its own book. After that you will have volumes that contain 3 chapters each. The prologue is simply that, and intro to the story, and is counted as Chapter 0.