There are several methods that will allow you to create a new notebook from your home screen.

Careful when choosing the name of the book,  

Be careful when choosing the name of your book, because it will no longer be editable and it will then dial the email address of the book. But you can then change its description, which will serve as a title. 

Option 1 :Create a new book from the menu on the left

You can create a new book using the search bar on the left, by clicking on the  button:

Option 2 : Create a new book from the navigation bar

By adding a new book

You can create a new book by clicking on the button on the navigation bar, at the top of your home screen.

By creating a new message

Using the same  button, you have a second way to create a new book.

This time, choose the New Message option:

This option initially allows you to create a new message in an existing book. But as the help message indicates. If the name of the book in which your message is to be sent does not exist, it will be automatically created.

You can therefore create a new book, directly adding a message and an attachment:

Option 3 : Create a new book from the book display page

You can create a new book using the  button, next to the existing books.

Whatever the method used, a window will pop up, enabling you to choose a book option

From scratch :

See article. 

Importing a CSV or XLSX file :

See article.

From a template :

See article.