Press down on the polished stainless steel battery cover of the AirTag and rotate it counterclockwise until it stops
Remove the cover and take out the old CR2032 battery
Insert a new CR2032 lithium 3V coin battery with the positive side facing up
Replace the cover by aligning the three tabs with the slots
Press down on the cover and rotate it clockwise until it locks into place
Check that the AirTag makes a sound to confirm the battery is installed correctly