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1. Create a hidden variable named sms_message. Populate it with the text string that should appear in the message body. 
2. Create a hidden variable named sms_addresses. Populate it with the comma-separated list of phone numbers of the intended recipients.
3. Insert the SMS-message sending question using the following steps:
   1. Insert an Android App Callout question, by going to Add Question > Advanced > Android App Callout.
   2. Open the form's XForms XML file, by going to the Form Builder Menu > Edit Source XML.
   3. Search for: 'odkx:intent' to find the instance of the Android App Callout question that you added above.
   4. Delete what is there, and replace it to match the example below. The "button-label" and the "data" attributes in particular for the "odkx:intent" element currently can only be set in XML. Pay special attention to ensure that
   5. Update each of the following variables with content that matches what you would like to use:
      1. "Send SMS"
      ,
      1. => Change this to the label you would like to see on the SMS Button
      2. /data/sms_addresses
      , and
      1. => Change this to the full path of the hidden variable that contains a comma-separated list of phone numbers
      2. /data/sms_
      message are configured appropriately.
      1. message => Change this to the full path of the hidden variable that contains the content of the message being sent

<odkx:intent xmlns:odkx="http://opendatakit.org/xforms" id="send_sms" class="android.intent.action.SENDTO" button-label="Send SMS" data="cc:xpath_key:concat('smsto:', /data/sms_addresses)">
	<extra key="sms_body" ref="/data/sms_message" />
</odkx:intent>

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