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