Eaudiobooks downloads to IPod

I use a MacBook but am not very proficient at anything but email and the internet. I downloaded Overdrive and have checked out some books from my library. I cannot download the books to my IPod. I have tried directly from Overdrive and also updated my ITunes and tried from there. The directions say to ITunes from file to add library, then to documents, then to mp3. I don't arrive there with documents .. only to documents. Can anyone help me, keeping in mind that I am basically a beginner on Mac? Thanks