While a book is on hold you can:
Once a hold becomes available, you will receive an email notification as soon as the title is available to borrow. If you selected automatic checkout when placing the hold the book will be automatically lent to you. If you did not, you'll only have 3 days to borrow it before your hold is canceled.
If you’re under 13 years old: The title will be automatically placed on hold for you. When it becomes available for you to borrow, you'll see a notification next to the Account icon.