David,
Regarding this comment:
However I want a template that will lengthen and shorten depending on the amount of content I am placing into it when creating a landing page from it.Marketo's landing page editor does not work this way and you will need to use Edward's method.
Here's the technical explanation based on my experience: Marketo's editor, to keep things friendly for people without coding experience, uses "absolute positioning" to place content items on the page and do not write the code to the page according to established
DOM standards (except for placing it within the three nested elements Edward defined above, so it will respect centering on the page, etc.). You will need to explicitly define the height of your container elements for each page you make.