The Unreal plug-in can be found in the program-data folder (typically in C:\ProgramData\Vizrt\VizArc) under Resources\unreal.
The entire VizArc folder needs to be copied into the Unreal installation folder (for example, C:\Program Files\Epic Games\UE4.24\) under Engine\Plugins or under Engine\Plugins\Runtime.
After copying the plug-in, restart Unreal Engine and ensure the plug-in is activated (it is active by default). To verify, open Unreal Engine and go to Edit > Plugins. You should find the Viz Arc plug-in by searching for VizArc.
The communication port that is used by this plug-in in order to receive commands from Viz Arc is by default 5647. It can be changed by changing the registry key in UEPluginPort in HKEY_LOCAL_MACHINE\SOFTWARE\vizrt\Viz Arc.