Don't worry this is easy like breaking a toothpick..
*Make sure you have all these needed things and other resources before we actually to start out and flash a Stock ROM for Galaxy Pocket
*Make sure that you device has some juice in its battery nearly 60-70% to avoid any risk of hanging up the process while flashing the Stock ROM
*Make sure the USB debugging mode is enabled. It can be managed under the Setting->Application->Development->USB.DEBUGGING.
*The data on your phone might get erased while flashing, so don’t forget to backup with Titanium Backup.
*Also you need a PC with the drivers for your phone installed. You can download drivers from below..
*Also this is a step to Unbrick a Samsung Galaxy Pocket (GT-S5300)
Step-by-step guide to Install Official Stock ROM for Galaxy Pocket.
*Double check that you have correctly installed the USB drivers for you Phone and Downloaded Odin
*Switch OFF your device first
*Now boot it in Download Mode Press and Hold the Volume Down button + Home Button + Power
*Now connect your Phone to the Computer and Open Odin ( Ensure that when you connect your phone is still in Download Mode.)
*To check that your device is connected successfully or not just notice the ID:COM boxes, once they turn Yellow (Sometimes Blue) means your device is now connected successfully.
*Now in order to select the Downloaded Stock ROM you want to flash, Simply Click on ‘PDA’ and click on the file which you have downloaded below. (Extract the .zip file) (S5300XXLF5_S5300BTULF1_S5300XXLF5_HOME.tar.md5)
*Once you are done with all the previous steps, click on the Start Button in ODIN and wait for the process to complete.
*Once the installation is completed your phone will restart. Once your phone is all started up, you are good to go and unplug you device
*And Final Step Hit ''THANKS'' If i helped you in anyway i can.... )
STOCK ROM: http://www.4shared.com/zip/SZzB-egN/...TULF1_BTU.html