This was me exploring Truffle and I got so many things wrong!
A proper example of using Truffle is the simple language included in their repository.
If you are looking for an example of how to just use Truffle, without all the mx build system stuff in the Truffle repository, have a look at https://github.com/fehrenbach/parsers, which uses maven for fetching dependencies and building. There's stuff about Scala in there, but that should not be needed, have a look at older commits.
A BASIC on Truffle
Generate an executable uberjar with maven:
mvn install
Run with default JVM:
java -jar target/tuber-basic-1.0-SNAPSHOT.jar fizzbuzz.tuber
Run with graal-enabled JVM: (this runs the program, but I don't think it does any clever compilation...)
/home/stefan/opt/graalvm-jdk1.8.0/bin/java -G:+TraceTruffleCompilationDetails -G:TruffleCompilationThreshold=1 -jar target/tuber-basic-1.0-SNAPSHOT.jar fizzbuzz.tuber