To create a Lead Magnet automation:
First, create the Email with the freebie or auto reply.
Then, create a Form and embed it on your website (click on Forms on the top menu) > choose between Pop up or Embedded > customize >choose segment where new subscribers who opt-in to this form should go.
Finally, create a Workflow (click Workflows on the top menu) to auto-send the email you created as a lead magnet to anyone who gets added to that Segment by opting in to the form, and voila you’re on your way to growing your list 🙌.
More to learn: