You can easily delete a book you no longer need.
Just click the Books icon beneath your book, and then choose Delete book.
A message will pop up: "The book can be recovered from your Recently Deleted library for 2 weeks." Choose DELETE or CANCEL.
Retrieving a deleted book
If you need to restore a book you've deleted, click on the Libraries button and you'll see a library called Recently Deleted. Click on this and you'll see any books that have been deleted within the last two weeks. What's particularly useful is that even if a student has deleted the book, a teacher can still recover it.
Now click on the 3 dot menu and you'll see the option to either Restore or Delete forever.
Here's the whole process: