I don't see a way to install that OS

Hello, if you have a physical CD, you need to make an ISO out of it first. Then, in WinUAE settings, select the «CD & Hard drives» section (under «Hardware»), click the "Select image file" button near the bottom of the window to browse for the ISO image file by expanding «My Computer» and selecting the Z: drive. Browse the Users/YourProfileName, find your ISO and click «Open».

Note that AmigaOS3.9 CD does not include Amiga Kickstart ROM. You need to deliver your own. Version 3.1 (40.68) is required for AmigaOS3.9.

For more details please refer to AmiKit Quick Guide: https://bit.ly/AmiKit-QuickGuide

No problem with the ROM. I've already imported it.

Not sure how to make an ISO, but I will research this.

Thanks
Gary

I got as far as my Desktop folder within my User folder but my AmigaOS ISO
doesn't appear (Disk Utility made it as a .cdr; I hope that's right)

The .cdr and .iso files are actually identical formats. Simply rename the suffix from .cdr to .iso and it becomes visible for WinUAE.

OK, thanks. That worked after I selected Start.
The screen that opens still talks about installing Picasso96
(I thought I did that first) and my cursor is the Mac cursor;
how do I get it to be the Amiga pointer on the small gray
screen so I can finish the installation and configuration?

I guess I should re-read the Guide again