Help Samsung Galaxy Note 2 GT-N7105 HELP!!

Can anyone help with the unlock of this phone? Samsung galaxy note 2 GT-N7105

I know nothing abou the unlocking however I have managed to find some cool tips out about secret menus and codes and now I have came to a brick wall. I can get to the service mode and only get so far. I believe I need to downgrade from 4.2.2 to 4.1.1 to be able to have the correct options to unlock? If anyone can assist it would be most appriciated!! I have installed samsung drivers to my laptop, downloaded odin plus samsung keis (which I don't know what it does)
Please help 😊