Downloading a file (not part of a campaign) with MailChimp

Downloading a file (not part of a campaign) with MailChimp

I've got a simple embedded MailChimp form (email addresss + submit button)
on my site. For now, clicking on submit allows users to subscribe to my
MailChimp list.
But I want that clicking on submit: (1) triggers a free ebook PDF file,
and (2) gets the user subscribed to my MailChimp list, ideally right away
without having to confirm subscription via some confirmation email.
Because the whole thing is a one shot event, there will be no campaign:
it's only about downloading a file once and having people who downloaded
it listed in a MailChimp list. So I have no idea how to achieve this.