I'm having trouble figuring this out. It feels like it should be a simple thing to do, but for the life of me, I can't figure it out. Does anyone have experience setting this up?
I am not sure what you are looking to do. There are a number of tutorials on youtube. Or check https://www.literatureandlatte.com/learn-and-support/video-tutorials/an-introduction-to-scrivener-1?os=macOS for their tutorials.
That doesn't cover it, unfortunately. I'm trying to add a small piece of text under each chapter title - excerpts from fictional documents. I've figured out that it's easy to add them with Vellum, so I'll probably just to it that way instead.