How to restore Factory settings in Samsung Galaxy S4(GT-I9500)?

NOTE : Before doing Factory data reset, it is advisable to take back up of your phone data as all your data will be erased and cannot be regained after completion of this process. CLICK HERE to take backup through Kies 2.5.

a). Tap on Apps as shown below :

c). Under Accounts, tap on Backup and reset as shown below :

d). Now tap on Factory data reset as shown below :

e). Now tap on Reset device and then tap on Erase everything as shown below :

This successfully restores to Factory settings.