CAESAR II uses the typical "right hand" coordinate system. So take your right hand and extend the first three fingers (counting the thumb as a finger) so they are all mutually perpendicular, and look at your palm.

Your index finger should be pointing up, which is the CAESAR II "Y" axis. The thumb should point to your right shoulder, this is the CAESAR II "X" axis. The middle finger should point to your left shoulder, this is the CAESAR II "Z" axis. If the CAESAR II graphics show anything else, then the model has been (manually) rotated.