First of all, download and install the Samsung USB drivers on your PC
Next download the root package for your device from above
Connect your phone to PC via USB cable and transfer the Root.zip file to the internal memory of your phone
Download the ODIN package and extract it to your desktop too
Disconnect the phone and power it off
Open the ODIN folder you extracted in Step 4 and run the Odin3 exe file as administrator
Now power on your phone while pressing the Volume Down + Home + Power buttons at the same time. This will boot your phone into Download Mode
Now plug in your phone to the PC. You should see an Added! message in the Odin window
Read more at http://dottech.org/149733/how-to-root-samsung-galaxy-ace-3-gt-s7270-gt-s7272-and-flash-cwm-guide/#AMFTCK4L4wAbEVAe.99