Ill Update this thread Regularly and edit it so as to make a sort of guide for them. So far ive found 1 skull. It was located in the room you start out in, behind a box in the back part of the room. I have also found 1 terminal located in the tunnel after you crash land on halo and you save the Marines trapped on that platform. after you get the warthog youll drive down into a tunnel and cortana will talk about the covenant battle channel not being secured, youll then drive down a small ramp and its at the back of a small hallway. you will see a flashing light, the light is the terminal.