Unfortunately it is technically impossible to monitor all IPs from a regular computer. This is because in a regular network, all computers talk directly to a router, without giving a standalone computer any chance to see what the others are doing.
In enterprise networks the monitoring is usually done at the router, which is either expensive hardware or a Windows-based server. Alternatively, the monitoring can be done by installing a monitoring server between the router and the rest of the network. We have an application called Bandwidth Manager, which can control users in a network with a router, but it's probably something you would not normally use at home.
With regards to NetWorx, since it's not possible to see the usage for all computers, NetWorx can only monitor traffic on the computer where it is installed. If you want to monitor traffic on multiple computers, you basically have two options:
Install NetWorx on every computer in your network. This can only be done if all your computers are running Windows. While NetWorx can only monitor traffic on the computer it is installed on, instances of NetWorx can talk to each other so that each instance is synchronised and shows the actual overall usage. In this case, devices like iPads, Smart TV or mobile phones will not be metered as they do not run on Windows. This synchronisation needs to be turned on in the NetWorx advanced settings.
If your router supports so-called SNMP or UPnP protocol, you can monitor all traffic via your router. This however will not give you a per-device usage breakdown and the monitoring computer must be continuously on to poll the router and collect the usage data. See the Router Monitoring page for more details.