Default [Q] Control phone with shattered screen. Need to enable usb debugging

Hello everyone. I shattered the screen on a MotoX and want to be able to control it from a PC.
According to the following page, it can be done...

But you need to have USB debugging enabled, which I don't. According to the following link that is still possible by sideloading adb. Unfortunately, most of the jargon in there is above my head. I don't really know what to do and I couldn't reply to that thread directly because I don't have permission.

Any suggestions on where to begin?