This problem was solved in the past by embedding a Mailchimp pop-up into my Squarespace site. Is that no longer an option? I now see only native Squarespace promotional pop-ups, and the lack of a second field to collect zip codes is really frustrating. I don't actually see a way to add a button. Where do I find that?
I tried changing the layout on the Squarespace pop-up to the only layout option on display that has buttons rather than an email field, but it's not working -- when that new layout displays with my text and photo, the button is gone and the email field is still there.