I've finally come back to this add-on domain issue and would like to reclarify.
If the primary domain is something.com then we get a directory structure like this :
public_html
Now when you put an add-on domain of thisisit.com you get a directory structure that looks like this :
public_html
.....thisisit
So
www.something.com will execute public_html/index.html
and
www.thisisit.com will execute public_html/thisisit/index.html
Would that be right ?
I want to be sure I understand how it works before I order it all.