To send SMS, you may go to Business Admin> Messaging> Create Standard Messaging>
1. Select Message type:
Email Message> select your email template or create a new template
SMS Message> enter your customised messages
2. Segment your target Audiences by adding rules
3. Schedule when to send the SMS
4. [Save & Schedule it] if you are done or [Save Draft] to continue editing next time
After completing the draft, you may do a test. Click on [TEST], Enter test recipient mobile number and send.