I had to scale the 6 and 3 to 1% to hide them. It would be better if there was a “hide” function for the numbers. Perhaps there is, and I have not yet found it.
Sorry, I don’t have screen capture software for video.
It was several settings, putting the various notes into the same voice column, then selecting the tuplet brace and picking “3” in the properties pane to show only a number and then “scale = 1%” to hide it. Perhaps there is some clever user with screen capture tools that can replicate this procedure. Possibly parts of the above are documented in the online documentation.
If no one picks up, I can do a text-based step list on how it was done, but a video is perhaps nicer.