To unlock and factory reset an android phone ;
(1) First you have to power off the device.
(2) Remove your sim card(s) and memory card to avoid loosing your data
(3) Then hold down the power botton + the volume down or volume up botton
depending on your phone . Power + VD or Power + VU
(4) Keep holding both bottons until it enters a formartig mode
(5) Then use the volume up botton to choose , choose “format and erease all
data” the system will remind you that all data will be lost do you want to
continue ? just press YES your device will reboot
NOTE : you will loose every data on the device after this process..