From the customer view in https://admin.webex.com, go to Workspaces, and then select the workspace that you want to update.
Go to Calling and click the cogwheel . Then choose a call service for the workspace and click Save.
(Optional) Go to Calendar and click Add Calendar so that people can use One Button to Push (OBTP) from their Cisco Webex devices. Then select calendar service from the drop-down menu and select Resource Group and add Email Address. Click Save.
Enter or paste the email address of the room device. This is the email address that will be used to schedule meetings:
This option requires the Hybrid Calendar Service. To configure the service, see the Deployment Guide for Cisco Webex Hybrid Calendar Service.
Add Services to an Existing Workspace with Cisco Webex Room, Desk, and Board Devices
If you've already created a workspace, such as a lobby or lunch room, you can still add services, such as PSTN, to the Cisco Webex Room, Desk, or Board devices in that workspace.