The one you were referring to is the Template hook. That's not what you need. What you need is to create a PHP hook. PHP hook != Template hook but you can have a product that has both a PHP hook and a template hook.

OK This is where IM not getting it. So I really do not need a template hook at all, simply create a product, and in the product I can call hookFrontendBeforeOutput($params)

That returns the $params['pageHtml']; , that I can then edit directly correct

Correct.