Run the following command
mvn archetype:generate -DarchetypeGroupId=org.apache.apex -DarchetypeArtifactId=apex-app-archetype -DarchetypeVersion=4.0.0-SNAPSHOT -DgroupId=com.example -Dpackage=com.example.myapexapp -DartifactId=myapexapp -Dversion=1.0-SNAPSHOT
Using your favorite IDE, open the project that has just been created by the above command. Write your application code and optionally operator code
Change to the project directory created by the maven archetype and run mvn package
cd myapexapp; mvn package
The Apex App Package will be at target/myapexapp-1.0-SNAPSHOT.apa