Default [Q] Unroot Telus HTC One M8

Hey guys new to the whole rooting world of android so there are some things I seem to have missed during this process ie. creating a backup of my stock rom.

I am trying to install an OTA update and I seem to be having troubles with this. Was hoping someone would be able to help guide me back to stock in layman's terms if thats possible.

Thanks in advance if anyone can help.