Power off the phone. Take out SIM card tray. Undo two small T2 screws. You need two plastic opening tools. Slide the tool to open a gap. Be careful not to scratch the metal rear cover. Then insert another tool. Keep sliding. Then you can see a gap here. Be careful not to scratch the metal rear cover. Then pry up the rear cover on the bottom of the phone. Keep prying up. Similar to iPhone here. Slide the plastic tool to separate the side of the rear housing. Mind the power button. Take you efforts. The same on the other side. Need some time to remove it. There is no adhesive. After slide along the rear housing cover. You can separate the rear housing and the front screen assembly now. Phillips screwdriver. Undo one Phillips screw. Remove metal bracket. Wire cable connector. Two extension cable flex connectors Battery connector. Release the black tape. Release connector. Motherboard cable flex. Hold the pull tap of the battery. Take your affords to pull the battery out. Black sticker underneath you can see here. Show the adhesive here. Install battery. Make it fit well. Reconnect the connector. Motherboard cable flex connectors. Battery connector. Black tape. And the wire cable connector. Put back metal bracket. Put back one Phillips screw. Power on the phone. You need to check out if the screen display perfectly. Put the screen assembly back to the rear cover panel Put the top side in first. Pinch down two sides. Don’t put too much pressure on it in case you broken the screen. Mind the button. Pinch down the bottom Check whether the screen works well by power on the phone. Check the ring silent switch and the volume buttons. It works well. And the power button. Fasten two T2 screws at the bottom in place. Put back SIM card tray.