Yes, that's pretty much like it. Please note that there are some small differences between the tutorial and the actual addon domain addition wizard. The main is that you don't need to fill in the folder name, CP will do it automatically for you, and the folder that will be created will have the same name as your addon domain. If you like to give it a name that you want, by typing it, you can still do it, but a different name would be confusing. The new domain web address will be
www.2ndwebsite.com.au . You can ALSO reach it as
www.2ndwebsite.1stwebsite.com.au and as
www.1stwebsite.com.au/2ndwebsite because adding an addon also automatically creates a subdomain with the same name (but not viceversa) .
To publish in that addon domain, in the publish window , in the field folder, you type "public_html/2ndwebsite" . You also need to create a folder on your computer, and save all pages of this new domain in that folder, so you wll avoid confusing pages between the two sites, and overwritting similarly named pages (index is the first one that would be overwritten)