How to replace power button on honor 8

I recently bought a replacement screen for my honor 8 after it was broken. I had changed it before with no issues other than my volume down didn't work but I was able to function without it. Now, I am not sure if the volume up or down works cause I can not even get the device to turn on. I can plug in the charger and the green circle pops up letting me know that it is charging, it's just not letting me turn the phone on. I think I might have ripped the ribbon that connects the motherboard. I would like to watch a tutorial on how to replace the part or a permanent fix that I can actually use since phone is not already turned on. (I can not download an app to change my settings.)