Do I need to build Google Play License Verification to use it?

Quick question that I'm sure anybody (but me) can answer.

I added Google Play App License Verification plugin to my project. But other than dropping it into my project, do I need to build anything. I.E., like after my .apk has been generated by unity?

The readme file found here displays a section on How to Use which states just to paste your "key". The next section of the readme talks about how to re-compile the java source.

My Question: Do I need to re-compile the java source?

OMG fingers-crossed that somebody who understands unity will at least take a quick look! Seems like other people have figured out how to run the example which came with the plugin. I am an IOS person and so I'm just fumbling my way through trying to get an Android version working. HELP puhlease!!