I think it will be better for you to go through the pipeline tutorial first. Once you have your custom configuration set up and looking something like you see here:
then it will be easier to add more custom code to include publishing and loading HDAs. I can go through this with you as you progress until you have the final pipeline.
They even have a good explanation of publishing in the section titled “Custom Shader Publish”. It explains how Shotgun collects items to be displayed in the Publish window.
By the way, how well do you know Houdini’s Digital Assets?