This should be included with Overloader, however if otherwise, copy the DLL files and this HTML file into C:\<Buzz Path>\Gear\Recorders\. If you want to use this Recorder plugin with some other software that supports these Recorder machines, please refer to their documentation.
In Overloader: Go to View -> Extended Hard Disk Recorder, and select the plugin from the list of plugins in the plugin selection dialog.
In any other program: Refer to it's documentation.
The multitrack Wav recorder is best used for post-production reasons, the recorder can record multiple tracks into individual wav files with sample-precise synchronization to be loaded into a multitrack editor such as SoundForge or CoolEdit Pro.