Repeaters not showing for mobile, or in layers

I first attempted to use a repeater with six boxes - three above, three below. After struggling with this, I guessed that the underlying array code would not allow me to get the container boxes to display at the same height for desktop view. I had been able to get the mobile view looking exactly as was needed.

Today, I added two repeaters (three across) from “Lists & Grids” and after some adjustments, got the page layout the way it is needed on desktop view. Now to make adjustments for mobile, right?

The repeaters do not show up at all, and are nowhere to be found within layers. Does anyone have a suggestion? It turns out that the repeaters don’t show in the desktop editor layers either, but I was able to make adjustments on the page.

Any ideas?