spark - sbt build tool
The spark documentation doesn't says (or maybe i missed it) about getting sbt tool if you're trying to build it on Windows. You need this to build, package and run scala code in spark.
This tool can be obtained here. Once you have this installed, you can fire up your command / cygwin command prompt and continue building, packing and running your code by following this guide.
basically it is just running sbt assembly.