You can use the Find Items app on your Apple Watch to locate a missing AirTag or third-party item that you’ve registered to your Apple Account.
See the iPhone User Guide to learn how to on your Apple Watch, then tap the item you want to play a sound on.
Tap Play Sound.
To stop playing the sound before it ends automatically, tap Stop Sound.
You can get directions to an item’s current or last known location in the Maps app on your Apple Watch.
Go to the Find Items app on your Apple Watch.
Tap the item you want to set up a notification for.
Tap Notify When Left Behind, then turn on Notify When Left Behind.
You can also go to the Find My app on your iPhone, tap Items, tap the item you want to set up a notification for, then tap Notify When Left Behind. Turn on Notify When Left Behind, then follow the onscreen instructions.
If you want to add a Trusted Location, you can choose a suggested location, or tap New Location, select a location on the map, then tap Done.