The Brotherhood Missions are Co-op missions.
They have a difficulty scale ranging from 1 to 5. 1 is very easy while 5 is exceptionally difficult. These are designed to be played by 2-4 players. There is no one way to complete the mission that is laid out before you. These missions are also designed to have players work together toward a common goal. it will take everyone present to deal with the guards, find entry and complete the missions.