Before flashing process you must will need to take a backup of your important data. Create an appropriate backup of contacts, pictures, videos, songs and other important files stored on your device before proceeding with the steps below, so that in case something goes wrong you’ll have a backup of all your important files.
You can safely recover your data to phone after flashing. The flashing process will take enough time to complete. So still wait for few minutes until flashing process will not be completed. Sometimes, firmware installation may delete everything on your device! Like, when you change the CSC of your device, knowingly or not. Now you can download latest firmware of your phone by just managing below download links.
Note: There are some needed things which must have every flasher. First of all one thing keep in your mind that you must will need to download correct firmware file on your PC. Then install any flash tool which you want to use as a flasher. Then must take a backup of your data before flashing.