How to provide formatting to my entire book at once

Hi guys and gals!
I’m using Scrivener to write a fiction book. My book is organized into one folder per chapter, and then one document per folder. I’ve been writing this for a fair bit (read: OMG, it’s been like…five years since I started this!!!). And because of that, I’ve got some serious formatting issues in my book. I’d like to apply one consistent font and indentation style to the entire thing in one go, and I’m having some difficulty accomplishing this task. Can someone give me guidance on the best way to achieve this? Not just for this book, but also my next?

Thanks all!