Hi! I have my AT&T Note 4 stock and virgin from any mod and i want...

I have a note 4 from AT&T with a firmware LYM47X.N910AUCU2DOI2 in 5.1.1 Lollipop stock and never modified! I want unlock the bootloader, install a teamwin recovery to make a backup of my original firmware to make root later, but, i not see anything about do that, if someone know how to...... i have the kitchen ready to cook this OS but i need make free my device before do that :(

HELP ME to help others in this forum, i want assist others :( contact me in this forum plz....
thanks and wide hugs!!!