When you define a campaign with a template in the Automation workflow, that campaign will be sent as a marketing email to new leads who subscribe to your brand and are imported via a CSV file in MailBluster. This means that when you import a CSV file with leads marked as subscribed, they will automatically receive the campaign you’ve set up in the Automation workflow. If you’ve set a delay, the email will be sent after the specified delay duration.
Automation emails are not being sent to those imported leads that are already stored in the Leads section with ‘subscribe’ status.
Also, if you fail to enable this trigger before starting the workflow, the subscribed leads will not receive automation emails.

Please note: Automation is a paid feature, and hence, MailBluster does not brand itself on these emails. There is no way to send automated campaigns without any cost.