First: Set up the Template
You would need to create the Template which is the actual email message.
You can create one from scratch following these steps https://support.feedbackwhiz.com/hc/en-us/articles/115001809248-Creating-Templates-Video-
To ensure your email message is compliant, refer to https://support.feedbackwhiz.com/hc/en-us/articles/360056085133-What-are-the-upcoming-TOS-changes-
Or you can load one already created and TOS compliant from here https://app.feedbackwhiz.com/templates/prebuilt
Second: Set up Custom Campaign
Campaign's use your saved email templates and apply rules and timing to send out those email templates by following these steps: https://support.feedbackwhiz.com/hc/en-us/articles/115001709687-Creating-and-Editing-Campaigns-Video-
To see the status of when your emails will be sent please check the Email queue page-https://app.feedbackwhiz.com/campaigns/email_queue
Inside this page, you will be able to see the shipped and delivery dates for each order and the queued date time which will tell you when the email will be sent based on your campaign timing rules.