• deploy the chambers, armoury, dungeons, throne room, and other rooms
  
• take care of the castle expansion
  
• repair damage on an ongoing basis
  
• extinguish fires
  
• build a moat

• ensure that the blacksmith forges swords and the armourer makes the armour
  
• see to the butcher slaughter the pig
  
• make sure that the farmer sows the field, harvests the crop and the baker bakes the bread
  
• ensure that the winemaker delivered the wine...
  
• ...and that the tables are laden with food

• resolve conflicts
  
• punish criminals
  
• take care of the spiritual development of your people

• suss out intrigues
  
• plan sieges
  
• negotiate with other kingdoms

• take control of plagues
  
• fight against epidemics
  
• deal with natural disasters

Remember that your king must be satisfied with your work! Do your best to keep the castle alive, the people happy and the army ready for battle!