step 1. download the respective firmware of the region where you live from here
step 2. Make sure you installed the drivers for sgm correctly
step 3. Download ODIN and ops file
step 3. Boot in download mode by pressing home+vol down+power key simultaneously. And finally connect the device to pc through USB.
step 4. Just select one package on odin choose OPS file and the md5 file downloaded in step 1, then start the process
step 5. Boom its done.