To connect a new phone, unpair it with an already connected phone, and then long press the [Settings] button on the Airpods charging case to reset it.
Open the [Bluetooth] function of the new phone, open the Airpods charging case and get close to the new phone. At this time, the screen of the iOS device will pop up and the connection can be completed according to the prompt. For Android devices, you need to go to [Settings] - [Bluetooth] for pairing.