How can I get the stage manager?

FoxFifth wrote:

Stage Manager is built into macOS Ventura. It is not available in iPads or any devices other than Macs or on Macs that are running macOS versions prior to Ventura.

While it is definitely not available on an iPhone, it is a feature of iPads. It's pretty cool.

Turn Stage Manager on or off on your iPad - Apple Support

Stage Manager is built into macOS Ventura. It is not available in iPads or any devices other than Macs or on Macs that are running macOS versions prior to Ventura. Access it through Control Center on a Mac. See details in Use Stage Manager to organize apps and windows on Mac - Apple Support

Thanks Idris. I thought I was too old to learn something new!

You're never too old for that!