You can use the Webex app to place calls on a Webex device when your app is connected to it.

• Call a space : When calling a space, all participants in that space are notified on their devices. 
During the call, anyone in that space can join by selecting the green Join button.

  Select a space, and click the Meet icon.

• Call a contact : Select a contact and click on the video call icon. Choose Webex Call .