Open in your browser Onesignal website https://dashboard.onesignal.com/login (ask for login)

Click on the name of the account

Select SMS

Click on the top right corner of the new message

1. Add a Campaign name
2. Click the + include segment (All SMS subscription)
3. By default message (EBH portal)
4. Add Text message ( You can add emoticons)
5. Select + additional media (this image will be on top of your text)
6. Send TEST message to your phone number to verify the message before is launched
7. Send and review

By sending messages this way, you can track who clicks messages, time, and details about the campaign in the dashboard of your Onesignal account.