I posted this question before but it was "protected", so I can't answer it. So I'm reposting it so that I can answer my own question.
I can't get my Blackberry Priv to connect as anything other than charging via USB. My PC isn't recognizing that a device is connected. I've downloaded and installed the Tethering and USB drivers here. I restarted after installing them. On the phone, it never gives a notification that it has connected as a charging device, and I know that's what you'd normally click on to change to file transfer. Also, in the settings options, in Storage and USB, there is only information about device storage, nothing about the USB connection type. I've enabled developer options. In there, I've turned on "USB debugging" and "Allow USB debugging in charging mode". I'm at a loss as to what else would need to be done to get file transfer working, and honestly I'm completely confused as to why it's not showing up in the Storage & USB options. I'm having a hard time finding anyone else mentioning this issue.