Make sure your iPhone or iPad has the latest iOS or iPadOS
Turn on Bluetooth
Turn on Location Services
Turn on Find My iPhone
Remove the AirTag battery tab
Hold the AirTag near your iPhone or iPad
Tap Connect when the setup screen appears
Choose a name for the AirTag
Register the AirTag to your Apple ID
Tap Done
Check the AirTag in the Find My app
Attach the AirTag to the item you want to track