First download your rom.
Once your have downloaded it extract it to your desktop and you should get a tar file.
Now turn your phone off and put it into recovery mode. That's done by holding volume up+power+home.
Once in there clear the cache then in advanced clear dalvik cache too. You can use the volume to navigate and power and home to select and go back.
Make sure your battery is charged up.
Once done put your phone into download mode. Volume down+power+home and accept the disclaimer. (If you own a jig its good to use instead never mind if not)
Start Odin and select the .tar file you downloaded in the PDA section. Do not change anything else. Connect your phone and click start.
What for if to finish.
If when all is done it still boot loops, pull out the battery and put it back in. Boot into recovery mode. Select wipe data/factory reset. Then select wipe cache partition. Reboot the phone.
When the phone starts up don't spend too much time setting it up as its best to do another reset. So when you have skipped all the setting up go into the phone dialer and dial this code: *2767*3855#. This will do a good format off the phone and put it back to as new.
After doing all this try updating your phone via kies to make sure everything is ok and that you are on the latest version.