[Q] AT&T S4 MK2 4.3 to Lollipop GPE topic

I'm coming from a stock mk2 4.3 for my att i337 s4. i want to go to this rom. can someone please point me to the right direction/link so i can install this. i need step by step please. i wanna be also able to use it on tmobile cause that's my carrier right now but using att s4. also want to have root access. so basically carrier unlock, root, and lollipop rom. is it possible for this i337 thats on mk4 4.3 stock?? any help please!! thanks.!!