We need embed the moodle book view in the main page course.
Normally, you can find a list of links inside the sectiosn of a moodle main page course. For example, you can find the item "Sample book" linking to the URL url /mod/book/[url removed, login to view]
What we need is show the view of the book embedded in the section as you can see in the attached image, so that you don't need click "Sample book" to visit the book.
The starting point is the course format Buttons
([url removed, login to view])
And you can find inspiration here:
[url removed, login to view] -> official Moodle documentation about course formats
[url removed, login to view] -> This course format shows directly the book view instead of the list of items. It would perfect if you can use like "Main activity and other resources" instead "Single activity"