sign-in with authorized adobe ID

I connected my Kobo Mini to download a public library book (first time) I used to borrow books from my Sony ereader but now I switched to Kobo. I have set up and authorized my Adobe ID. However on my Kobo device, if I click on the public library book it says "Oops, this document couldn't be opened. It is protected by Adobe Digital Rights Management and is not currently authorized for use with your Adobe ID. Please sign in with the authorized Adobe ID and try again."

So where do I sign in or go from here?