Musescore4: Where's the Muscescore3 "Instruments" eqivalent?

I used to go in under "Edit" from the menu in Musescore3 and the "Instruments" window was available at the bottom. In Musescore4 I can't find Instruments anywhere, so far. I did notice that there's a shortcut, letter "I" that also works in Musescore4, so I guess I'm OK for now even the option seems to have been moved elsewhere (or omitted entirely?) in Musescore4 .

What I'm really hoping to do is create a 2nd staff that automatically follows the 1st staff, in my case so that conventional notation will automically update along with tablature staff. That's something I used to have available in another piece of software. I can't remember for sure but I seem to think that I did get it going once under Musescore, without my constantly having to copy-paste from the tablature into the standard notation score. But I guess I ought to open up that discussion elswhere.