Update README.md

Author: NathanSweet

README.md

@@ -4,6 +4,10 @@ This is a small Windows utility that uses [libusbjava](http://libusbjava.sourcef
 
 This Java project can easily be extended to have the PowerMate knob perform other actions.
 
+## Installation
+
+For this software to work, the libusb-win32 driver needs to be installed for the PowerMate. [Zadig](http://zadig.akeo.ie/) is the easiest way to do this. The latest version of the tool is [here](https://github.com/EsotericSoftware/powermate/releases).
+
 ## License
 
 PowerMate is released as OSS under the [New BSD license](https://github.com/EsotericSoftware/powermate/blob/master/LICENSE).