If you are using the Custom email campaigns.
First create a template, go to Campaigns > Campaign Manager.
To create a new campaign:
1) Click the Create custom email campaign button.
2) Enter a Campaign name and select the various options using the dropdown box.
3) Click Save.
You can repeat the process above to create multiple campaigns but be sure to review the Amazon TOS to ensure you stay compliant and only send out proactive emails that are approved by Amazon.