When you open Overdrive, you should open to your Bookshelf, which should show a book, Welcome to Overdrive Media Console. At the Rey bottom of your screen in the black bar, you should see an icon that is a circle with 3 horizontal lines. Tap on that. Under more options is a help section you may find useful.
To get books,, tap on the Get Books icon.
at the bottom, it should say, Add a Library.
tap on that.
type in your library name or zip code to get a list of libraries.
Select your llibrary tap on the star next to the library name to add it to your list of libraries.
Now when you open overdrive, if it is at your bookshelf, tap in the circle icon, select get books and your Libtrary should be listed.
select your library and the app will go to the library website.
From here you can search or browse for books.
When you find a book you want if its available, add it to your cart and then check it out.
You should have enter your llibrary are info.
Download the book,
from there you need to go back to the bookshelf to open the book, use the back arrow button in the top eft corner.
you should check with your library to see if the offer any classes.
if you need more perhaps someone else will jump in, or, when I get to my computer I can type more detail. I'm on my ipad, so it's basically one finger typing, plus dealing with the iPads bizarre autocorrect.
Be kind to yourself :-). Overdrive is not super user friendly. I went to my library, then figured it out on the PC, then on the NOOK, yet lost a book or two in the process. You may wish to search this forum, and/or google publisher ebook wars (& NPR has has a few stories about this), to learn why books are not always available via the library, in NOOK or any digital format. I like reading on the NOOK, yet still read traditional books too. Good luck!