What happens next?

How to locate the asin to an audible audiobook
Open up the audible website and log in to your account, if you haven't already done so.
The search box you'll need is only available if you log in to audible's site. However, this should be easy; if you have an amazon.com account, you'll also have access to audible.com.
Locate the audiobook from their large collection of audiobooks. Whether you've purchased it or not, their asin's can be found.