Download and extract the appropriate ZIP file for your platform.

The <plugin>.p file can be copied to any directory where you keep your plugins. We recommend using a manually created plugin directory to separate third party plugins from plugins shipped with LightWave 3D. This will simplify upgrades of LightWave 3D.

Now use the Edit Plug-ins panel (alt-F11) of the Add Plugins menu item to add the plugin file <plugin>.p to LightWave 3D.

You can also copy it to

%userprofile%.NewTek\LightWave\2018.0\plugins

to allow LightWave to detect the plugin automatically.

You are of course free to copy the plugin file to another location and add it manually.