Please you try it according to below procedure:

Step 1: Turn on the phone’s Bluetooth.
Step 2: Open the AirPods charging case cover（Don't take out the headphones if the pairing is unsucessful）.
Step 3: The connection interface will show on the phone.
Step 4: Click on the ICloud to connect with phone ( hold on the button on the back of charging case) ,then wait for the phone screen to show that the connection is successful, then take out the headphones and use it.

Package Includes:  
     2x Bluetooth Earbuds (left.right)
     1x Wireless Charging Case
     1x Lightning Cable
     1x Manual