When you set up an Addon domain, the system automatically creates a folder with the same name as the Addon domain (unless you choose a different directory name in the “Document Root” field during the setup).
For example, if your Addon domain is hostghostexample.net, the folder path will be: /hostghostexample.net
All files for the Addon domain hostghostexample.net should be uploaded to: /public_html/hostghostexample.net