The downloadable .ens file (compressed as a ZIP file) is referred to as a 'Reaktor ensemble', and can be loaded into the FREE Reaktor Player sound synthesis program created by Native Instruments (or the complete version of Reaktor]]).
By running Reaktor Player (or Reaktor) on your laptop/desktop computer and loading this .ens file you will be able to play the sound demonstrated in the demo videos below.
The Bowed Strings Reaktor Ensemble is designed to work with the Multi-Key version of the Motion Synth App, in conjunction with the Motion Synth Grip.
Both Reaktor Player and Reaktor (paid version) can be loaded as a VST or AU into your preferred multitrack software (e.g. GarageBand OSX, Ableton, Logic, Pro Tools, Cubase, Reaper) allowing you to play and record the Bowed Strings Reaktor Ensemble directly within your multitrack software.
Videos, diagrams, and notes on playing the Bowed Strings instrument sound are available below.
Here is an example of the playing techniques described below being used in combination:
Download a .pdf and .png of the diagrams here: Diagram Instructions for Bowed Strings
Note: In order to utilise pizzicato control as explained in the video below you need to import this extended version of preset 5: