I want to pop-up

I want to pop-up to only display after the user has scrolled 30% down the page. But I can't find instructions about where to place the code: [wd_hustle id="test-opt-in"] on the page to make it pop-up after the user has scrolled down. I added it at the end of the blog post content, but that simply displayed the object at the end of the post (not popping up after scrolling 30% down the page). I set the pop-up settings to appear after scrolling 30%.