Follow each step carefully.
Align the Taptic Engine with its designated slot in the enclosure.
Press the Taptic Engine connector firmly onto the motherboard until it clicks into place.
Use a Phillips screwdriver to reinstall the screws that secure the Taptic Engine.
Place the battery shim back into its position above the battery.
Press the battery connector back onto the motherboard until it clicks.
Align the back cover with the device and press down until it snaps into place.
Press and hold the power button until the device turns on.