1. Go to Home-> Messages
2. Select an icon to whom you want to send sms. For example for entire community or all owners etc.
3. There you will get two options like Send template based sms and the other one is Send custom sms.
a. If you select template based sms, sms will be sent to mobile numbers which are in DND list
b. Custom sms will be sent to mobile numbers which are not in DND list
4. After selecting you can send an sms immediately or in a scheduled time.