To build from source:
1) Install Maven (http://maven.apache.org/).
2) mvn clean install
3) Find output in "target" directory.

Alternately:
1)  Use the included "maven wrapper" (no separate installation necessary) 
2a) For linux/macos (or similar):
      ./mvnw clean install
2b) For windows:
      mvnw.cmd clean install
3) Find output in "target" directory.
