How to track down a sudden traffic overuse

Just been shocked to see our home usage go from ~2 GB per day to ~50GB per day starting Christmas eve. I'd like to track down more details to figure this out.

We have a few Win 10 PCs, 3 iPads, iPhone. I've noticed --- thanks to Networx app --- that one laptop downloaded 40 GB yesterday. That's like 10 hi def feature length movies. Windows Defender did find a Trojan. Is there a way to drill down and see:

1. Time of day that downloading took place; and
2. Where (URL) the data was downloaded from?

Cheers

You can see the time of the day under Hourly Rates shown below. Unfortunately it can't tell you where it was downloaded from, but if you had the Ignore local traffic within the LAN option on, you can see what apps downloaded the data at the Applications tab.

Thanks very much Andrew.

I've never fully understood what "Ignore local traffic within the LAN" means... does that, for example, ignore downloading a file from one computer to another on the LAN? If so, would it ignore even if the computers are connected via Wifi?

Yes, the option activates the built-in network driver that filters out local communications, for example copying a file from computer A to computer B within the same network, whether it's WiFi or cable.