I'm new to this but it seems the board I want to print out prints out too small how do I know how to set it to the size that it's intended to be printed out for the project?
First we need to be sure you are printing from the right place.
EAGLE 5.3
FILE>PRINT
That opens the print dialog window. In that window there are X and Y setting for Calibrate. Used these to adjust so that you printer produces the right size.