In my program (MicroStation, and no, it's not free) here is an idea of the printing workflow;
First, you have to know what your output paper size will be (for me, that's usually the working area of the laser, or cnc machine.)
Then draw a shape at that size.
Now, IF you want the end result to be scaled (it doesn't have to be), you simply scale that shape by the factor you are scaling. ie if you want a 2:1 printout, scale the shape by 2.
then draw everything at 1:1 (truescale) makes drafting MUCH easier.
Then slide your scaled border over to show what will fit on a sheet.
and (and here's the part I think you are missing) we place a "fence" which tells the software what we want to print by "snapping" to the corners of the scaled shape. (mind you that shape doesn't have to be scaled, it can simply be your paper size.)
Then hit the "print" button in the software.
It then takes the area you've defined by the fence; fits that area to the paper size defined by the printer selected.
You then just have to hit "send" and there's your print.
There are a bunch of windows print drivers that actually output a PDF if that's what you want for your final result.
Hope this wasn't too confusing...
I haven't touched AutoCAD since... the Early 90s... But the same process should apply.
Since the CAD working area is limitless, you have to define what you actually want to print and it's probably just looking at your view or window at this point.
Hope this helps.