mobile

Hey guys... So I'm REALLY new at this whole rooting thing, so please forgive me if I am not aware of any terms related to rooting and such.
So basically what happened was this:

I decided to root my Galaxy S4 (sgh-i337 --- AT&T) using the towelroot method. I had to use this method because my phone is currently running Android 4.4.4 KitKat (TouchWiz) and it worked fine. SuperSU was installed, Root Checker said my phone was rooted, it was good. I tried to install CWM using Odin, and I got the "RESET" or "PASS" from Odin, which I thought that it meant that it worked. However, when I tried to go into Recovery Mode, it went into Stock Recovery Mode. I started to look at other tutorials, and I came across another one that involved flashing your phone's respective CWM .img file from your phone itself (transfer the .img to your phone's SD, and then flash it from your phone using the app, Flashify). But when I tried to go into Recovery mode to see if it worked, it gave me the yellow triangle with an error message, "System software is unauthorized by AT&T" or something like that. I tried to look at other posts, and there was a general idea that I needed to flash the stock Kernel. Now, the way I rooted the phone in the first place, I already had two different ones downloaded. One was flashed, towelroot was used, and then the second kernel (which was the one that originally on my phone before rooting) was flashed. After that, it was rooted. So me, being the complete noob I am at rooting, decided to re-flash both, in order, to see if that cleared up the error message when trying to get into Recovery Mode. This did not solve the problem either.

Again, I would like to apologize for my lack of knowledge on rooting and such, so please forgive me for my incompetence. And yes, I know that there are other threads on topics like this, but I have tried several things and it has not worked. Any help on how to fix this problem (and how to install CWM properly on my phone - since it is updated to 4.4.4 TouchWiz - or if I should use TWRP instead, because I intend on downloading the Kangapop GPE ROM(and how to install that for my specific model/software version)) is greatly appreciated, thanks!