To change your opt-in within Mailchimp:
1. Go to your LIST > Sign up Forms > Confirm Subscription Email
2. Create a new link (suggested to keep the one above and do a new one) for your PDF file. All links in Squarespace can be files (there's 3 tabs in links, content, files or external - just choose file) drag new PDF there to host it on your site.
3. Now we need the link to the PDF - open your new uploaded PDF in a new window and grab the link in the browser address window.
4. THIS is then the new link you want to paste into your automated email to confirm subscription.
Above is the info Meg provided. HERE STARTS A NEW BLOCK. INFO ADDED BY INGE. ADDING THIS BLOCK TO HAVE A SPACE TO KEEP ALL THE LINKS FOR MY OPT-INS.
Opt-in 3 - General with MME offer on page 4