Adding a custom pop-up based on the page a user enters

Hello! I have a customer who wants to customize the promotional pop-up based on what page they enter the site (example - if they come to a blog page with a recipe page from pinterest, have that page have specific promotional pop-up, vs. if they just come to the home page). Has anyone done anything similar? I am assuming we can set this from adding html at the page level, but I'm not sure where to start with that.

Thanks in advance for any help!

Siena

I recently had a client, I created a Newsletter Block on each page, then used JavaScript to turn it into Popup. You can try this idea.