It's a digital PDF submission, but you are welcomed to do anything you want with it, including printing it at some point in the future.
The templates are just there to assist folks if they are stuck, and you do not have to use any of them as part of the project. This is your own creation! The only request I have is to keep it "booklet sized, and horizontal," which is 8.5"wide X 5.5" high. The decision behind that request is so that it all matches with other adventures, and I also hope people do illustrations that span the entire 2-page spread - which was part of the fun of the original booklet.
I hope that helps!