There isn't really such a thing as a template in FuelPHP.
There is a template controller, which will allow you to set a view as a 'page template', and will automatically render it when your controller action is finished.
So the template in that controller is a normal view. Passing sections to it is nothing more then passing variables to it, that may contain another View object (for example a header or a footer view). http://fuelphp.com/docs/general/views.html has an example, under 'nested views'.
If you want a more flexible system, you should have a look at the Theme class, which works with themes (multiple), templates, partials, theme fallback, central view folders, etc.