I have installed 2.3.1 and I do not see the editors like I see in the demo website where there are editors for left middle and right is there anything I am missing on my install.

I'm not sure what the left and right areas are that you are referring to. It sounds like you just want to add another HTML editor field to page.

If you look at http://doc.silverstripe.com/doku.php?id=tutorial:2-extending-a-basic-site you can see how to do this. Look for the section explaining this code:

function getCMSFields() {
$fields = parent::getCMSFields();

$fields->addFieldToTab('Root.Content.Main', new CalendarDateField('Date'), 'Content');
$fields->addFieldToTab('Root.Content.Main', new TextField('Author'), 'Content');
   
return $fields;
}

But what you want is to add an HTMLEditorField: http://doc.silverstripe.com/doku.php?id=HTMLEditorfield

Ok, I see what you mean. Yes, you need to write PHP code to add three more text editors on the Homepage class.