Please i have been searching the whole internet, but can't get the answer to my question. How can I unluck the the bootloader of my Samsung Galaxy Ace3 Duos. Please any help will be appreciated. Thanks in advance.
Samsung devices don't really have a "Bootloader", like the Nexus (and some other Android) phones. However, Samsung devices have an "Odin Mode" (sometimes referred to as "Download Mode"), and they have "Recovery". For rooting the Ace3 I believe you want to go into Odin Mode and then connect your phone to your PC. From there you can use the Odin Program to flash the root file onto your phone.
To access Odin mode while your Ace3 is powered off, press Volume Down + Power + Home.
NOTE: Before doing this you want to make sure you have "Developer Options" and "USB Debugging" turned on in your system settings.