I am new to BookyAI and I do not know where to start. Is there a tutorial?

Yes, from version 1.9.17 BookyAI has a built-in Guide. Click "Guide" at the bottom left of the app, under the menu. It opens "Your first book, step by step", a list of five steps: connect an AI engine, start your first book, let BookyAI write the chapters, give it a cover, export the finished book. The list ticks itself from what you have really done, and the next step to do is opened for you with two buttons: "Show me how", which starts a guided tour of that step, and a button that takes you straight to the right page. Below the list there is a guided tour for every page of the app, and a few tips. If you open BookyAI for the first time with no book and no AI engine connected, a welcome card offers a two-minute tour of the whole app.