Structure.Gantt API is a work in progress. You will find that some of the packages are documented less than others, and some are not documented yet.
We're continually working on API improvements and documentation and will make the javadocs and other parts of the documentation more complete with future releases.
You can download javadocs from the Maven repositories into your IDE.
To learn more, choose the correct API artifact, and download Javadoc JARs, see Structure.Gantt API Versions.