Write your first message
Messages in Seos are send as emails. Go to Settings > Messages. There click Add new message (you need an active subscription to do this). On the following screen you are asked for a subject and the actual body of the email.
Messages on their own don’t do anything, but they are fundamental to automations.
When you’ve written your message, click Save. Your message is by default saved as a draft. As a draft, it can’t yet be used in an automation, but it’s useful to edit later. Is your message ready? Check Active, click Save—you can now select it in an automation.