How to make Roll up 3 closed captions.

I'm curious about how to create CEA-708 closed caption roll up 3 captions in Premiere.

How should I edit the subtitles?

And no matter how much I specify roll up 3, it doesn't change.

The style setting of the new caption track is also disabled, so there's no way to do it.

If you know how to create roll up 3 closed captions, please give me some advice.

Thank you.