This can be very annoying and CPanel doesn't seem to document it, or it's not found or made as obvious as it should be.  It's always funny when I find it more difficult to work with a control panel than to do everytihng manually without CPanel or even Plesk.

So once again, the default serve path for contents is: /usr/local/apache/htdocs and this is especially applicable when accessing Apache by just an IP which is unbound to any domain at this point.