Well, I don't know.
What are you trying to import exactly? Just the work that is on paper space?
Basically, the layout is your paper space where you would put your borders and set up sheet sizes, etc. The model space is where you do all your work, annotation, etc. The viewport allows the "paper" to show the "model", so you can plot.
If you are just trying to import your border to use, I would suggest starting a clean template, inserting copying the border you want to use to the layout tab, and saving it as a .dwt template. You can also have different tabs in that template for different sizes, each with a border drawn on paper space. Then, when you start a project, you set it up to ask for a template (rather than defaulting to one). When you choose your .dwt, all the different sizes show up, and you just choose the one you want.