Hello. Please follow the instructions below.
- Press and hold the Power button + Volume down button at the same time for about 30-50 seconds or the until the phone lights up.
- Scroll to 'Wipe data/ factory restore' (scroll with Volume Down)
- Confirm selection with the Power button
- Scroll to 'Yes---delete all user data'
- Again, confirm with the Power button
- Wait until you see Wiping complete
- Short press the Power button to 'Reboot now'.