How do I reinstall stock HTC Sense 6?

[AC Question]

I have a HTC One M8 and tried to install a GPE rom on it. After getting confused, I stopped but I had installed InsertCoin rom. The rom didn't install correctly, but now I can't get it back to the version of android that came on my phone. My phone is the AT&T model, with TWRP installed. The version of InsertCoin is 6.0.1, and it doesn't even boot, it just hangs on the HTC splash screen. My CIN is CWS__001 and my version-main is 1.58.502.1. I followed the guide on WonderHowTo called 'How to Get S-Off on Your HTC One M8 to Install Custom Firmware & Mods' and got stuck.