obi302 setup issue

So, i finally was able to get my Obi302 provisioned and online, but it shows as unassigned. We have 9 users, 8 of those with desk phones. All have a phone # and 1 phone is a common phone with no number in a common area. I can see the device in the device list and it shows online. How can I assign it to a phone # and start using it?

help article says ATA should be assigned to a phone user or common area phone with a calling package and direct phone number, but HOW!??