No Operating system on phone?

Long story short, I installed Xposed and my device went into a boot loop or just stuck at the T Mobile splash screen.

I factory reset and format data to try and fix the problem.

Now I don't have an operating system on my phone.

Where can I get the system for my phone? I have a SM-910T

I was on COD6 and was reading about COG2 being abailable now?

What are the differences?

Thanks for input