In order to start working with SMS, you need to have App Directory enabled. If you do not have App Directory yet, contact your Customer Success Manager to get started.
You also need to have your Zaius phone number for SMS configured. To check your phone number, navigate to the SMS tile in the App Directory, then switch to the Settings tab. Under the Configuration section, you can see whether a phone number has been generated for you. If you do not see a number, contact your Customer Success Manager.
Once you have access to App Directory and your phone number has been generated, you can start using SMS in your campaigns.