firt book

Open your document in Pages
Open the Pages document that you want to publish as a book.
On iPad or iPhone, tap the More button , then tap Publish to Apple Books.
On Mac, choose File > Publish to Apple Books.
Online at iCloud.com, click the Tools button , then choose Publish to Apple Books.
Tap or click Continue, then sign in to iTunes Connect. If you've never signed in, on Mac click Create iTunes Connect Account. On an iPad, iPhone, or online at iCloud.com, sign up for an account.
Tap or click Continue. Beyond this step, any changes you make to the Pages document won't appear in the published book. If you need to stop the publishing flow and make changes to the Pages document, just close the publishing window.