[Q] How to install custom ROMs (I'm daft) topic

So I the SGH-I537 model (AT&T) and I'm running 4.3 on my phone. I Have it rooted with the methods listed the in general form and the root works great, although I can't find a guide to install ROMs for anyone running 4.3 just 4.2.2 I tried to follow the method in the 4.2.2 thread but quickly determined that it wouldn't work do too my baseband ending in different characters than what was provided (1537UCUBML2) If anyone knows of a thread or can link me to some information to help me get my phone to stock 4.4 that'd be great, thank you in advance!