Preparations you will need to make on your Samsung before we can do the unlock :
A.If your phone has Android version 5.0 ,5.0.1 or 5.0.2 (to find Android version go to Settings/About phone)
1.Go to dial window and type *#0808# and from under USB Settings select "MTP+ ADB" and Reboot the phone
B.If your phone has any other Android version beside those from point A.
1.Go to dial window and type *#0808# and from under USB Settings select "DM + Modem + ADB" and Reboot the phone
If *#0808# does not seem to work,please try *#7284# instead. If you have a custom firmware have to restore to stock firmware for this settings to work.