Welcome guys we will replace the battery apply heat with heat gun on back cover of the phone, with blade make space between back cover and body, remove back with x-ray or like x-ray. Any plastic sheet does not damage fingerprint scanner. Flex here is fingerprint scanner flex clean place of the back cover on around the body. Remove all the screws from protection cover, remove protection cover from main board, disconnect subflex lcd flex and battery and fingerprint scanner flex, connector from main board pull out. Adhesive strips for battery. Remove now remove the battery.
You can use adhesive, strips or double side tape or gum like t8000 install battery in the body connect battery finger lcd, flex and subflex connector to the main board. Install protection cover on the main board, put back all the screw on the protection cover, apply gum on the place of back cover around the body, install back cover of the phone. All you have done successfully. Thank you for watching you.
Source : Easy repairing tips