$ sbt
sbt> compile
sbt> assembly
sbt> exit
$ java -jar ./target/scala-2.13/akka-artery-remote-sample-assembly-0.1.0.jar 25521
# On another console
$ java -Dconfig.file=src/main/resources/application2.conf -jar ./target/scala-2.13/akka-artery-remote-sample-assembly-0.1.0.jar 25520
And type your messages.