As you can see, oca.org has put up a notice that there is a space for authors to sign and sell their books.
If you're asking your publisher to ship some books to the council site, the address is:
Bellevue Hyatt Regency
900 Bellevue Way NE
Bellevue, WA 98001
Please let me know your interest. You can write me at firstname.lastname@example.org