[cflsystems]

The ListChild tells the rebuild process where to inject the content of the template.
In this case it is in list "invoice.base'. So the content of your new template will show alongside with all other templates that belong to that same list.
The "weight" parameter tells the rebuild process where in the the stack within this list to inject the template. In other words "weight" it's used for sorting - sorting is in ascending order, lower to higher number.

All you have to do is to have this template and include the ListChild line then rebuild the cart - from there the process automatically will pick up on that and do whatever needs to be done.

If you do not have the ListChild directive in the template you will have to have View class that shows the template and include it there (or without the list directive your template will show when the View class is called from some other template or class).


If you include the list directive in the template file you don;t even have to have a View class to support it unless you need to show info in the template that is not already available for that view - then you need View class to pass that info to the template.