Reviewing the implementation
To check that network monitoring is working, compare any logical map drawn by the tool with the physical map you drew in step 1. If the two match pretty well (it is unlikely that the maps will match perfectly) then you can be fairly sure the tool is functioning correctly and will be able to monitor the network adequately.
It is worth repeating this process whenever you add new devices to the network. This will ensure that new devices are included in network monitoring activities and that the network monitoring software is able to detect changes to the network topology.