Students and Staff are photographed the same way.  Face your subject to your Main Light.  Instruct your subject to sit on the seat fully - taller subjects who's feet reach the stools should have both feet flat on the stools, very tall subjects may put their left foot on the floor and leave their right foot on the stools, in the case of small subjects their feet may not touch the stools and this is fine, simply make sure they are seated fully on the seat and their legs dangle with the natural bend of their knees.  Subjects should also have their hands relaxed on their thighs (not on their knees!), sit up straight, with relaxed shoulders turned toward the Main Light, with their face turned back to the camera, and a pleasant expression or smile. When sitting many individuals tend to tilt their head to the right instead of having their head "on straight".  Instruct them to tilt their head to the left slightly.