To Create a Class Notebook,
Select the Class Notebook option (1) in the left section
Click on the Set up a OneNote Class Notebook button (2)
And Select the From Existing Notebook Content option (3)
Click Next
You can Copy Content from other Notebooks into this Notebook's Content Library or Teacher-Only Section
Do this by Selecting the Add Content button
And Finding the relevant Resources
The Student's Private Space is what the student will see in their own section
You can rename (1), delete (2), and Create New (3) sections
When Done click Create in the bottom right.