Go to http://www.santacruzpl.org/ematerials/
Click on Overdrive on left side (this link tells you how to download Overdrive books to your iPhone ) but just follow below instead...
Click on "Log in" and then it should have your library card number already, and just click "Sign in"
"Search" (upper right) for books you might like. Enter "Science" for example
Click on 'borrow'
Click on 'loans' in the Overdrive browser window on your laptop, and it'll show you this new book in your collection.
Plug your iPhone into the USB on your computer
click on the brown "download mp3 audio book".
A little box will open up, take the default which is "open with Overdrive for Windows" and click OK at the bottom of the little box
It'll ask to save it in c:\users\observatory\documents\My Media\MP3 Audiobooks which is OK, you're just going to send it to the iphone anyway . So click 'OK' You'll see a progress green bar at the bottom of the box. Should download much quicker to the laptop than it will in a moment to the iPhone.
A bigger box will appear as it downloads. The download just takes seconds. On the top menu of the bigger box you'll see transfer and click it
You'll now see a small box and it should show your iPhone by default as the device to send it to. Click next and it'll start transferring; probably take 30sec to a minute.
Go back to the loans page on the browser connection to Overdrive and download and then transfer the next book, etc.
To Delete Files from your iPhone Music...
* from iPhone desktop, tap settings / general / storage and iCloud / music (or whatever) and you'll see all your books there and their size, typically a couple hundred MB . Top right corner tap edit
* then you'll see a red '-' appear and tap it and confirm delete
Go to that folder in Overdrive and you should see your books. In Overdrive along the top bar click on "transfer" and it'll search for the iphone. When it finds it, let it transfer. It'll take just seconds to maybe a couple of minutes.
On your iPhone, click on "Music" and then under that click "Albums" to find your books to play them.