Use the Clock app on Apple Vision Pro
The Clock app 
To learn more about using the Clock app on your Apple Vision Pro, see the iPad User Guide.
Tips and tricks for Clock on Apple Vision Pro
To see the current time, look at your palm, then flip your hand over.
To quickly start a timer with Siri, say something like “Siri, set a timer for 30 minutes”. Find out what Siri can do on Apple Vision Pro.
You can have multiple timers running at once; just tap
to add another.Alarms, stopwatches and timers continue even if you close the Clock app.