Text on path disappears

I'm using Photoshop 2019 on a Windows 10 PC. I'm trying to do something that I think should be simple - put text around a rounded rectangle. I know I have enough text to cover all 4 sides, but only three show. And I can't figure out how to get the text to keep wrapping so it ends up where it starts.

When I put the text cursor inside the text, there is no anchor or anything to move. If I put the text cursor in the text, then select the Direct Selection Tool, I can move where the text begins, but I can't flow the hidden text.

The user guide was no help. I've been at this an hour and am very frustrated - it should be easy. Any help would be appreciated.

Thanks,

Marcy