Use the exposed clear plastic pull tab to peel the battery off the adhesive securing it to the iPhone.

Be careful not to pull the plastic pull tab too hard as it can be ripped off very easily.

Remove the battery.

If your replacement battery came in a plastic sleeve, remove it before installation by pulling it away from the ribbon cable.

If your replacement battery came with an uncreased cable, carefully crease the cable into the proper shape before installing the battery into the phone.

While installing the replacement battery, temporarily connect the battery connector to the phone to ensure proper alignment. Once the battery is glued in place, disconnect the battery connector.

Perform a hard reset after reassembly. This can prevent several issues and simplify troubleshooting.