The address book in your dashboard stores your endpoints: the phone numbers, VoIP devices and other systems that receive your forwarded calls. Once an endpoint is saved, you switch to it by selecting it from the list.
Give each endpoint a clear name so it is easy to recognize, for example “Head Office”, “London Sales”, “Mobile - Sarah” or “After Hours”.
The address book is shared across your entire account. Any endpoint you add is available right away for every phone number in your account, so you only need to set it up once.