Basic use means that you configure the plugin from the POM. However, it doesn't run automatically, but on demand:
mvn apache-rat:check
To achieve that, a section like the following needs to be added to your POM:
<build> <plugins> ... <plugin> <groupId>org.apache.rat</groupId> <artifactId>apache-rat-plugin</artifactId> <version>0.16.1</version> </plugin> ... </plugins> </build>