What about new Braille feature in Ios 14?

Hello Everyone,
this morning I installed the new Ios 14, and I'm starting "descovering it. I'm really exited, like a little child. The firest thing that I did was go to see the Braille Features, and I found something new called sometihg like automatic Braillespeed in scroll or something like that (I don't know how it calls in English), however I don't undersand what it means and what it makes. I connected my Braille display, and I opened a text, but it doesn't scroll authomatically, in additon it let you fixing the speed, but not activate or desactivate the option. So, someone knows something more about that new feature?. Many thanks in advance. María