Design of a new terminal

Recently my home town (Ottawa Ontario Canada Airport code CYOW) got a second terminal. I am a complete rookie at creating an airport and i don't even know where to start. I would like to update the scenery to include the terminal and to fix problems that are currently existing. The existing terminal is still in use so i can use the existing scenery in FS9. So if any one can help me out i would appreciate it.
Michael
P.S. I have AFCAD
Michael
P.S. I have AFCAD