Hmm, been a while since I've done it, but I think that rather than copying it into a new template, you need to save it as a new file, then zoom in and start working. To get rid of the stuff outside your new borders, break your shapes at the border (i just make a box for the border to start), then you can put new lines in that match your borders and multipoly them back into shapes. I haven't reinstalled CC yet after I rebuilt my computer, so I can't go through and step-by-step it for you, but those are the concepts. Maybe one of our regular CC users can detail that a bit more for you.