Bricked my galaxy pro 12.2 sm-t900

[AC Question]

I am new to Android, just left the "other guy". I googled a guide to root my device. Followed it using odin and md5 file. My devices screen went all weird, it was bricked. If I reboot I get the firmware upgrade encountered an issue. I can boot in recovery mode.

So I started researching everywhere on how to fix it. Hours later, and a bunch of programs installed on my computer, I realise I was supposed to UNLOCK THE BOOTLOADER. I didn't. All the guides I can find relate to an unlocked bootloader. Mine isn't unlocked so all the files and recovery images I try to download and install through Odin do not work.

Other guides pointed to this ADB and Fastboot program. However, when I run the "devices" command my tablet isn't seen by either, even though I have the USB drivers installed.

I am desperate, any help would be GREATLY appreciated.

 

[AndroidProf]

If your device is booting into the recovery mode, Odin should recognize your device. In any case, you can use Kies to make your phone install the official firmware again. If you're confused on how to use Kies you can just google Kies XDA Guide. Moving on, as for using the Fastboot binary, well you need to be connected to the computer while you are in the bootloader menu i.e. not the recovery but the menu you access before it. And once you're in fastboot menu only commands with the prefix "fastboot" will work i.e. any command with adb infront of it is pretty much useless.