I have no professional involvement and am just a reasonably informed enthusiast. I'm not sure to what degree your preparation to date has involved reading up about North Atlantic flying, the track systems and communications arrangements and the system of oceanic clearances issued to aircraft. If you think that might be useful at this stage, here are a couple of sites you might want to look at:
Gander / Shanwick Oceanic - IVAO
http://www.nat-pco.org/nat/MNPSA/MNPSA_2008.pdf - there is a "communications procedures" section in this lengthy document