[Q] other carrier's hardware on AT&T topic

Hi - this may well be the wrong spot for this - I hope not. I have been reading a lot the last couple days regarding my plan and I was wondering if anyone else had tried what I am going to do and if so could you offer me any advice? I use AT&T because it is the only data signal that is around where I spend my time. I am getting a T Mobile SGH -m919 and I want to use it on AT&T's network voice, text, and 4glte data. If anyobe has accomplished this is there a step by step guide? or how did you do it? Or do you think I should ask it over in the tmobile forum?