Thank you all for your responses! You have helped greatly. Let me answer individually:

AudioTrack:
Your information above looks great! I don't think you mean that it would allow Biab to play back all the instruments from the score, but if at least it can create the multiple staves, I could add in the instrument names later for printing out and sharing.
Thank you!

MusicStudent:
I actually have been using Musescore, which I have found very frustrating to use. If I enter notes near the right side of a page, it flips down to the next line before I'm thru adding notes! To avoid this, I have to minimize the page quite a bit, too much for my "old, cataract eyes." (Sounds like a nice name for a song!)
I have a small, ancient keyboard, which I just discovered has a MIDI output! All this time I've been poking here on my computer keys. I tried Cakewalk years ago... for a day. Maybe I'm "smarter" now. Worth trying your suggestions. Thanks!!

Mark Hayes:
What I did with the old Version 8 was simply enter music I liked, some Bach pieces for example, and listened to what Biab could do with it.
I never tried to write my own things, nor did I try mixing instruments for combos.
But I have two new purposes now. I'm learning to write (Nothing professional! Never had music theory, but I can "feel" what sounds OK), so I had hoped this program could provide everything I need.

The other purpose, though, will work very well. I'll be helping my sister with her flute playing while the pandemic keeps her community band membership muted, iyw.
She needs to feel she's playing with other musicians. We think this is the way to go.

Thanks again folks! I guess I'll try to learn Cakewalk (my curiosity is revived), or just keep using MuseScore for the writing process.
Cheers!