Generating the documentation PDF: Run mvn process-resources
Resulting files are in the /target folder.
Publish the documentation to confluence: Run mvn asciidoc-confluence-publisher:publish
Do check the setting in the POM.xml :-)
If you want to document in the Arc42 style, there is a repository which already contains the structure. You can copy that into your own repository: https://github.com/arc42/arc42-template